# User:Phol ende wodan/YANI/IRC archive

Contents

1 Identification mechanics

1.1 List of existing informal ID mechanics
1.2 Set of possible items

2 Spells

2.1 Charm monster nerfs
2.2 Making utility spell failure matter
2.3 Changes to advanced spell forms
2.4 One-time-use spellbooks
2.5 Wielding spellbooks
2.6 Ritual spells
2.7 Miscellaneous

3 Object materials

3.1 Properties of weapons
3.2 Effects of gear
3.3 Elves and iron
3.4 Metalworking

4 Point buy for starting characters

4.1 Starting stats
4.2 Starting inventory

5 New roles

5.1 Alchemist
5.2 Artificer
5.3 Druid

6 Alchemy

6.1 1 + 1 = 2
6.2 Sink alchemy
6.3 New alchemical objects
6.4 Alchemy skill

7 Cantrips
8 Monster AI changes

8.1 Smart monster attack strategy
8.2 Group AI
8.3 Golem AI
8.4 Miscellaneous strategies

9 Resistances
10 Thief stones
11 Crafting

11.1 Craftsmen's Guild
11.2 Metalworking
11.3 Player crafting

12 Trap scaling

12.1 Floor traps
12.2 Container traps
12.3 Door traps
12.4 Magic traps

13 Terrain

13.1 Other new terrain types
13.2 Changing terrain glyphs

14 List of shorter YANIs

DEPRECATION WARNING: This page has been deprecated in favor of the new YANI Archive. This page will no longer be updated and will probably eventually be removed.
This page lists YANIs that have been discussed on several NetHack-related IRC channels on Freenode, so they don't end up ignored and forgotten.
Attribution will be listed whenever possible. I make no claim to any of the ideas. Feel free to add any other YANIs from IRC to this page, and to use or implement any of them as you see fit.
How these are retrieved: I log the #nethack, #nethack-dev, #hardfought, ##nethack-discord, ##nethack-variants, and #nethack4 channels. (If people are discussing YANIs on channels not listed here, let me know!) The logs are searched for strings like "yani", "yet another", and "feature request", with some surrounding context. Sometimes there's enough discussion of an idea to warrant more than a row in the table, and so it gets own section here.
Things that are not added to this page include:

Variant developers (and only variant developers) talking about planned changes to their own variant. Possible changes to their own variant that are variant-agnostic are still fair game.
Evil Patch Ideas.
Ideas which are fully realized already in some variant or have been in previous versions of vanilla NetHack.
Some YANIs for dNetHack-specific things that were suggested among an audience of dNetHack developers, because there are a lot of these and they tend to get recorded by the dNetHack developers quickly.
YANIs by only me, which are here instead.
YASIs, which grew to be a long enough list that I moved them to their own page.
Identification mechanics
Contributions by ais523, FIQ, jonadab, aosdict
The main idea here is to make the identification game less regimented. Currently, a rational player (who will not take the risks associated with direct use-ID) is restricted to indirect use-ID (and monster use-ID) of most objects until such time as they can find a general, book, or scroll shop, at which point they can price-ID the scroll of identify and other items. Once identify is known (and could be blessed), the good items (as determined by price ID) can be fully identified. This is problematic because it's not at all a gradual process, and it feels like it should be.
Some ideas have been floated to remove price ID outright (presumably, a shopkeeper would pay the same amount for each item of an object class as they currently do with amulets). This has some advantages; price ID is tedious, encourages stashing to some extent (because stashing near a shop where you can ID new things is good), and roguelike players who don't primarily play NetHack tend to hate its price ID system. In this case, either the scroll of identify should start out identified for all characters, so that identification doesn't take forever to get off the ground, or some other mechanic should be added so identify is easy to pick out for spoiled players.
If price ID is not to be changed, it should become less regimented and predictable, and less necessary of a strategy. The entire idea of price tiers doesn't appear to be based on anything much, and having items nicely organized into tiers makes it easy to disregard entire classes of items once their base prices are known. Ideas include:

Change price ID so that each item is assigned to a "band" of possible prices. There are four price bands, and each item class has its base price randomized based on its band. The price bands show up on unidentified items, e.g. "an expensive scroll labeled KIRJE". Some items might fall into more than one price band.
Fuzz the prices of items so that it's not possible to definitively say what an item is, only that it's cheap or expensive.
One way to do this is to scatter the base price of each previously tiered item each game on an interval so that it overlaps with the intervals from other previous tiers, perhaps a random number from 1/2 the original price to 2x the original price.
Or, do away with tiers entirely and simply scatter the base costs permanently. A ring of free action might be 240 or 260 base, because it's on the higher end of usefulness in the former 200 tier. Some fuzzing would probably be needed here to keep things from being unambiguously identified.
Other ideas to reduce the reliance on shops:

Reduce the potential consequences of use-testing items so it's not as terrible of an idea, such as giving a warning for reading way out of depth spellbooks.
Make scrolls and spellbooks in particular partially identifiable outside of a shop without having to formally identify them or guess based on frequency (which are currently the only ways to identify them outside of a shop):
Higher level spellbooks could be heavier. D&amp;D does this.
Make spellbook appearances more complex based on level. A simple color indicates a 1-2 level book, an unusual color or appearance indicates a 3-4 level book, a very odd or ridiculous appearance or material indicates a 5-6 level book, and a completely over-the-top appearance indicates a level 7+ book. (Example: "red", "steel", "bone", "jewel-encrusted"). Shuffling of the random appearances would need to be changed so that the books retain an appearance in their original bracket.
Make scroll label length (or, more complicated, its number of syllables) roughly correlate to its cost. The correlation could be fuzzed a bit, so MAPIRO MAHAMA DIROMAT is probably a 300 zorkmid scroll, but is certainly no less than 200, and NR 9 is probably something really cheap, but might be 100 zorkmid.
When you read a spellbook, you are given a menu with three options:
Give the book a cursory glance-over. This can fail with low Int/XL but is fairly unlikely and has very minor failure effects. If successful, it identifies the spell level of the book. Takes 1/10 the usual spell study time.
Briefly study the book but don't try to learn its spell. This can fail with mediocre Int/XL but will be reliable at high ones. Moderate failure effects. If successful, it identifies the spell contained in the book. Takes 1/3 the regular spell study time.
Study the book normally with normal failure effects and normal spell study time. Learns the spell if successful.
List of existing informal ID mechanics
Weapons: don't usually need to type-ID since there aren't randomized descriptions. Currently there is no way to learn enchantment like there is for armor.
Armor: most of it doesn't have randomized descriptions, but for those items that do, there is basically only wear-testing and price-ID. Wear-testing is fine assuming the player is able to check for curses, but only on armor types that don't have autocursing gotchas (a rare uncursed helm of opposite alignment or dunce cap).
Amulets: price-ID doesn't even work; the player has to use-test (safe enough assuming they can verify it isn't cursed or remove its curse, since none of the bad ones autocurse).
Scrolls: only price-ID
Potions: monster use identifies most of the beneficial potions (with the notable exception of gain energy), but this is a slow process. Dip-testing identifies the potions of polymorph and sickness, and a few other harmful potions can be dip-tested with a unicorn horn. However, there are still some bad potions (paralysis) that remain unidentified by these processes, so quaff-IDing is only safe if the player has identified the bad ones already.
Spellbooks: only price-ID
Rings: sink-ID is pretty unambiguous, but the chance of losing the ring makes it unhelpful unless you have duplicates, which isn't very likely until later in the game.
Wands: engrave-ID (and fallback on zap-ID) seems sufficient.
Tools: not many are randomized, but none of the ones that are have debilitating use-IDs, so use-ID seems sufficient.
Gems: touchstones and unicorns, seems sufficient.
Set of possible items
Items (perhaps only heavily randomized object classes, so NOT armor) can be inspected somehow, or else come pre-inspected, and your character is able to conclude that the item is one of several possible things from that object class. The number of these possible things can depend on role, and the "fakes" are randomized every game.
Example: a character inspects a potion and confirms that it is either healing, acid, or sleeping. All potions with this appearance will provide the same three possibilities. It's actually acid, but without other identification methods, or ruling out healing and sleeping, it can't be discerned which of the three it is.
Has some problems with the interface; a character shouldn't inspect everything and then have to type-name it. Perhaps this could be automated somehow.

Spells
Contributions by ais523, FIQ, Chris_ANG, aosdict, jonadab, NeroOneTrueKing, stenno, K2, mtf, Demo, Novel

Charm monster nerfs
Most people agree charm monster is too powerful, too low-level, and needs to be nerfed.

It only works if you're not wearing any armor. (This is apparently how D&amp;D does it.) Alternatively, its chance of successfully charming is reduced the more armor you're wearing.
Make it more reliable than it is now, but it always fails if you have other pets. (You can then only have one pet at a time without using scrolls of taming.)
It only tames one monster at a time. (Make it a directional beam with a maximum range of 1.)
It only pacifies monsters, and can't be used to tame an always-hostile monster.
Make it do what the temporary pet code in the Bard patch does: the monster remains tame for a fairly short amount of time and then reverts to whatever it was originally.
Split into three spells: pacify monster (peaceful for charisma*2 turns), charm monster (tame for Charisma*2 turns), and dominate monster (tame permanently or for a long time).
It only works on *monsters*, and doesn't work on intelligent beings.
Making utility spell failure matter
The problem: casting utility spells at high failure rate, such as identify at 95% fail, is a mere inconvenience to players, since they can sit in a closet with a stack of food and wait for their Pw to recharge until they succeed. This is not really a problem with combat spells, since the penalty for failing to cast the spell correctly is a disadvantage in combat, where time matters.

Large penalties for failing to cast a spell, like a 1% memory loss and 50 hunger.
Failing to cast a spell locks it for a certain period of time. It would be hard to make this not turn into an even slower grind for utility spells, since the lockout period could just be waited out.
Make spells never actualy failable, but Pw cost is increased proportional to the failure rate, specifically: real Pw = base Pw / success rate. Under this formula, a 15 Pw spell at 95% fail becomes a 300 Pw spell at 0% fail. This means the Pw cost should be exposed in the spellcasting menu rather than failure rate, even though failure rate still needs to be calculated. Maybe use different colors in the spellcasting menu to denote spells you can cast now, spells you can cast by waiting to recover more Pw, spells you can't cast even at your current maximum Pw, and forgotten spells.
Changes to advanced spell forms
Advanced spell forms are slightly problematic. Certain spells (fireball and cone of cold) which have advanced versions automatically kick in when the player is Skilled or above, and can't be cast using the lesser form even if the player wants to.

Some variants give you the choice of casting the basic or advanced form, but this suffers from an interface annoyance (an extra y/n prompt) and the fact that the advanced form is not actually any more difficult to cast.
Advanced forms are castable even at Basic skill, but have a higher failure rate.
The advanced form appears in the Z menu once you are Skilled.
The advanced forms are implemented as higher-level never-generated spellbooks, e.g. "fire storm" and "frost storm". Reading the basic spellbook automatically teaches you the advanced spell as well.
This allows you to balance them separately; in the case of fireball and cone of cold, the lesser spells could be dropped to level 3 or so and the advanced forms elevated to level 6.
The advanced forms are broken out into completely separate spellbooks that must be discovered and learned separately.
This makes the balance of spellbooks a concern, since it would add more books of a certain school.
Both of the ideas that involve higher level spellbooks may create a problem with the Z menu only allowing 52 different spells if more advanced forms come along, not that that can't be worked around.
Skilled+ casting does nothing to the actual spell effects, but allows you to cast the spell mentally.
One-time-use spellbooks
Instead of books having spestudied charges which leads to a lot of issues with polypiling, you read them once and they disappear, but you get 3 times the spell memory.

This is intended to remove spellbook micromanagement.
Spellbooks would need to be considerably more common than they are in vanilla. In FIQhack, where this was originally discussed, spellcasters generate with books, and the level of dropped spellbooks scales well as the game progresses since more dangerous monsters carry higher-level books.
This addresses polypiling by allowing the player to polypile the book as much as they want, but they can only read it once.
Slight nerf for people who finish their games in under 60,000 turns, since they can't use a spell for free confusion.
Also a problem for people who play very long games, because they will need to find or write replacement spellbooks; however, this was sort of already the case.
May make polypiling unknown spellbooks too popular, since an unknown spellbook is likely not to be the one you want, or you have price-IDed it and know it's something you will never use, and you can now poly without consequence. Perhaps address this by giving polymorphed spellbooks an elevated chance to become blank, and blank spellbooks do not poly into anything else.
Wielding spellbooks
The wield slot is fairly underused among object classes, and there are a number of interesting bonuses we can add to spells if the corresponding spellbook is wielded.

Decreases failure rate of the wielded spell (utility spells might need to be made higher-level/harder to cast to maintain balance).
Or decreases Pw cost of the wielded spell.
Allows you to cast the wielded spell even if completely forgotten.
Allows you to cast the spell without knowing it already - the Z menu gets an additional "-" option to cast from the spellbook in hand if you don't know what that book is.
Casting from an unknown spellbook will immediately check for reading success as if you had read the book: if you succeed, it then moves on to other checks like whether you have enough power, etc and you may cast the spell. If you fail, you get a random failure effect appropriate to that spellbook.
Ritual spells
More powerful and more expensive spells which have some esoteric effects you can't get otherwise. The main differences between ritual and normal spellcasting are that they consume valuable, hopefully non-renewable components, take a number of turns to cast instead of taking effect instantly, and may require you to be in or set up certain circumstances.
Various ritual spells that have been proposed:

Ball spells which consume a gem as focus and create a ball of elemental power that hits surrounding squares but not you. (Long casting times would probably make rituals infeasible for combat though.)
Temporarily increase your carry cap by a great amount. (Other new intrinsics as required.)
Resurrect a corpse as a tame monster (necromancy).
Grant temporary intrinsic life saving.
Single controlled polymorph with a greatly increased duration.
Summon a demon, demon lord, or demon prince. Requires 5 cursed candles and a marker (to draw the classic pentagram). If summoning a named demon lord, it's either random or there's some expensive way to control who shows up. The demon lord could be peaceful, but with current behavior this is useless. Possibly summoning them allows you to make a pact with them.
Remove the graveyard status from a level (would need to be expensive, and perhaps involve the Book of the Dead, and multiple different headstones).
Grow a tree. This consumes at least a piece of fruit. For anti-farming the tree should probably not produce fruit or bees when kicked.
Create a portal between two levels of your choice (doesn't work with the Amulet obviously, but otherwise works)
Create an artifact (that is, you somehow imbue an item with properties it can't normally get).
Bless items. Consumes a blessed scroll of remove curse.
Genocide a genocidable monster. Consumes a figurine of that monster plus other costly things.
Reverse genocide a monster. The monster may or may not have to be normally reverse-genocidable. Consumes a figurine of that monster plus other moderately expensive things.
Charge something. Requires a rare ingredient - perhaps a dilithium crystal.
Summon tame elemental(s). Among other things, ingredients include: a potion of water, any beatitude (water); a rock (earth); lit candles, a lit oil lamp, or a lit potion of oil (fire); an amulet of magical breathing (air).
Create a magic lamp. Needs an oil lamp (of course) and a figurine or mask of a djinni (or possibly a nearby live djinni).
Make the current level non-teleport. Requires a scroll of teleportation and that the caster be standing on an anti-magic field at (?) either the start or the end of the ritual.
Create a fountain. Requires a statue of a medium-sized or larger monster, which gets destroyed (by turning it into the centerpiece of the fountain). There may be potential for wishing abuse; perhaps the fountain should be flagged so that it can't produce a wish-granting water demon.
Turn a regular knife into an athame. Components include other bladed weapons with positive enchantments adding up to 20 or something; all of these charges will be drained to +0 in the creation of the athame. The resulting athame is +0, regardless of the charges on the component weapons or original knife.
Create a tame golem or golems. Requires a large amount of total weight of objects made out of the golem's material.
Ritual spells come in spellbooks like usual, but aren't stored in your spell list. Instead, reading the spellbook prompts you if you want to begin its ritual and tells you the necessary ingredients and circumstances you need to satisfy as preconditions. If you meet all the conditions and answer yes, you initiate the ritual. (For simplicity, this should probably burn up / expend all the components instantly.) You cannot begin a ritual while in the process of casting another ritual; this should probably be implemented as a precondition.
Apart from the component cost, rituals act as a constant drain on your Pw until the ritual is complete. If something distracts you in the middle of the ritual, you can go take care of it and then resume the ritual as long as you have the Pw left to finish it. (You could also drink gain energy during the ritual.) The only way for a ritual to fail, possibly backfiring with bad effects, is for you to run out of Pw while it is incomplete. 
In addition to its preconditions, each ritual also has some postconditions: common to all rituals is that you have been casting the ritual for at least some length of time, but there may be others, such as standing on the square where you began the ritual, or have another item, or kill a monster, or something. There may also be other conditions such as "moving off the space where the ritual started breaks and halts the ritual".
Every time you stop casting a ritual (whether it succeeded or failed), it increments the spellbook's spestudied field; the book will eventually disintegrate after casting it a certain number of times.

Miscellaneous
Bump the spell of sleep up to level 3 or 4.
Wielding a quarterstaff confers the same benefit as wearing a robe but does not stack with it (implemented in FIQHack).
Wielding a wand of nothing confers the same benefit as wearing a robe but does not stack with it.
Wielding an identified wand which matches a spell (wand of light -&gt; spell of light, wand of death -&gt; finger of death, etc) drastically reduces your failure rate when casting it. Perhaps casting the spell while wielding the matching unidentified wand should identify the wand.
Add a spell of collect arrows: it magically retrieves all objects on the current level that you've thrown or fired at some point in the past. (Possibly limited to weapon class objects).
Object materials
Contributions by AmyBSOD, aosdict, Chris_ANG, jonadab, bug_sniper, ais523

Properties of weapons
Iron - good against fairy, elf, and fae creatures
Gold - associated with the sun, so good against undead. Blunt gold weapons get a d2 damage bonus due to being heavier.
Platinum? Copper? Metal? Wood?
Effects of gear
Mithril body armor prevents bisection.
Elves and iron
Elves take extra damage when hit by iron. Not as much as silver, but still appreciable.
Elven players take a small amount of damage when putting on or wielding iron gear, but get no further penalty. (dnethack hurts their regeneration rate while wearing iron, which is another option).
Possibly some detrimental effect when wielding iron weapons as well, a to-hit or damage penalty, or negating bonuses from dexterity, strength, and skill, or something.
This is balanced by elven racial equipment being better (not improved; it's already better).
Metalworking
Would be a pretty neat addition as a service that offers things the player can't do on their own (probably not a shopkeeper service though), and some things they could do on their own but lack the resources. In particular, silvering has a lot of potential if the object materials patch is used. Also see #Crafting on this page.

Point buy for starting characters
Contributions by ais523, jonadab, aosdict, Tarmunora, FIQ
Point buy is an idea originally from ais523 that is intended to address startscumming by unrandomizing starting stats and inventory and letting the user spend points on stats and equipment however they like. dtsund's class overhaul proposal also addresses unrandomization of starting inventory by simply removing all the random chances to get items, but doesn't involve point buy.

Starting stats
Any point buy for stats is likely to involve a tedious interface. Developers could get around this by making it options-only, perhaps in a way that allows the user to say "buy to get my Strength up to 10, and my Int up to 9, and randomly pick the rest", but specifying it per-role could get annoying.
It's important to allow people who want to start and splat games rapid-fire to do so, and it would be preferable if new players didn't have to learn the complexities of a new interface.
The rc file must allow the user to specify starting stats per-role in this case, or specify that they want random stats.
"Dump stats" like Cha, and Int and Wis for non-spellcasters, allow people to buff their important stats at the expense of unimportant stats, which may indicate some underlying balance issues with these stats or that the stats can have too wide of a starting range.
Starting inventory
Even in a non-point-buy system, for starting inventory in cases like for Monk and Wizard where the player gets a random spellbook with equal weight among the possible choices, the player should be able to select which.
Any point buy system for inventory should probably be options-only, since designing an interface to do so would be complicated.
Naturally, items like magic markers and rings of polymorph control cost lots of points, whereas things like apples and oil lamps cost only a few.
Some items should probably have maximums.
This would come at the expense of players who actually want different nonrandom starting inventories and don't want to have to edit their rc file every time.
If the player's options leave some or all of the available points free, the game will randomly buy items until there are no points left.
Unspent points should probably convert into a certain amount of gold.
Possibly the default items are expressed as a list which consumes most or all of the points and is sorted from highest priority to lowest, and ones the user specifies get moved to the beginning of the list, which will push the low-priority items into the range of not being able to be purchased.
Certain items, like the knight's lance and probably most armor, should not be purchasable, and the character always gets them.
FIQ proposed a system in which you can specify one item, and the game will try to reroll your starting inventory many times until it gets that item. Since this is effectively built-in tool-assisted startscumming, it gets tracked as a conduct.
New roles
Contributions by Demo, aosdict, Grasshopper, Tarmunora, jonadab, ais523, FIQ, Chris_ANG, NeroOneTrueKing, Luxidream, K2, greqrg

Alchemist
Would require overhauls of several systems, but it's at least fun to discuss what the mechanics of such a role would be, and it's now being more seriously considered for dNetHack (for up-to-date discussion, see https://etherpad.net/p/dNethack_Alchemy).

The main form of combat is to create phials of potion (where 1 potion splits into many phials), which can be tossed at enemies to cause potion effects on them. The main potions used are things like acid, paralysis, (lit) oil, and confusion.
Phials come in all the same types as normal potions but have somewhat weaker effects.
You can dip a stack of empty phials into a potion to fill them with that potion (up to some maximum).
Thrown phials have the same exact splash damage effect on things as throwing the potion would produce, but drinking it is a small enough dose to only cause the splash damage effects to the drinker. Requires some balance so that splash damage is useful against monsters but not useful for the player to drink for beneficial phials.
Phials can be dipped into potions, but nothing can be dipped into phials.
The quest artifact is the Philosopher's Stone.
The quest leader is Nicolas Flamel and the nemesis is an Avatar of Death (like Death, but weaker).
More fun possibilities here if you have the object materials patch.
Its base item type could be a ruby (but perhaps not because dnethack makes the Heart of Ahriman a ruby) or a garnet, based on its color in Harry Potter, or an opal.
Can also create alchemic gizmos: smoke bombs from potions of blindness, firebombs from potions of oil, all lighter and more numerous and useful than the base potions.
Start with all potions identified.
Could start with an alchemy kit, which is a rare tool find for other roles. NeroOneTrueKing proposed a set of mechanics for an alchemy kit:
Has 3 compartments. The first accepts only potions/phials of polymorph (or perhaps it just has charges and you can recharge it by using potions of polymorph).
The other compartments must each only contain items of the same material.
A success chance is displayed based on the amount of polymorph potion available, the weight ratio of the two compartments, and the materials themselves (metal can transform into metal relatively easily).
A successful use swaps all of the materials of the two compartments.
Needs mechanics such that in an Alchemist's hands, no potion is useless.

The invoke effect of the Philosopher's Stone is heavily debated.

It creates potions of the Elixir of Life. This potion cures disease and restores lost attributes, but most importantly it grants temporary intrinsic lifesaving. If you die with intrinsic lifesaving, you lose the remaining time for the intrinsic.
Creating potions is way too powerful since the player will be able to bank them, so nerf this: perhaps you can only get Elixir of Life by dipping the Stone into a potion of full healing, or something. Or Elixir goes bad after a while and reverts to water, making it usable for before a fight but not for stashing.
The Elixir should not be _more_ powerful than a potion of full healing, or the invoke effect of the Staff of Aesculapius - healers should be the best at actual healing. Probably, getting lifesaved from intrinsic lifesaving will only restore enough HP to stay alive a little longer.
The Elixir gives a large temporary boost to HP regeneration.
No Elixir of Life; it instead turns potions of sickness into (extra? full?) healing.
The Stone can turn metal objects into gold or can turn rocks into gold pieces when rubbed on them.
When dipped into gain level or gain energy, transforms the potion into polymorph.
A really great Alchemist implementation would probably involve a full alchemy overhaul which adds herbs and fungi, harvesting ingredients from corpses, cooking, and interesting ways to combine everything. The challenge with making this is how to make it useful for other roles and not just the alchemist.

Artificer
Artificers can innately see charges on things and use wands at a higher skill level than everyone else.
Starts with an inventory of consumables comparable to vanilla wizards', a scroll of charging, offensive wands, a magic marker, and random tools.
Starts with all armors (magic and nonmagic) identified and all tools identified.
Restricted in nearly all weapon skills like a monk, or can only reach Basic in a few ones like knife.
Quest involves lots of golems.
Quest artifact grants double damage with tools and gives blessed charging when invoked.
Gnome is a playable race.
Also see User:Jonadab/ClassOverhaul#Item User: Tinker.

Druid
Intended to be a more balanced form of SLASH'EM's doppelganger race, druids are highly attuned to nature and possess innate shapeshifting abilities.

You begin the game with polymorph control and get polymorphitis at XL 5 or so.
Possibly you start with a wand of polymorph, or potions of it.
Inventory could be severely restricted, so you have to figure out how to do most things through polymorph.
You have the power to change into a tree, which will make most monsters ignore you. While in tree form, you are immobile but regenerate HP and Pw faster. Orcs might attack you with axes, a la Tolkien.
Without extrinsic polymorph control, your polymorph control limits you to changing into forms with the M1_ANIMAL flag.
Possibly have limited access to #polyself outside of wizard mode, so they can change intentionally and not randomly. Would work best as an ability with a timeout, or cost Pw outside of wizard mode.
Possibly, the monsters you can polymorph into must have a certain base level that's tied to your XL somehow (maybe XL/2). If their base level is too high, you can't polymorph into them.
Your controlled polymorphs always succeed - you will never accidentally fail and "feel like a new woman" with the 20% chance that all other roles have.
You are seriously bad at combat in your regular form, having very little weapon skill (nothing can be advanced to Expert, possibly not even to Skilled), and physically weak in your normal form. Combat in a polyform should be incentivized enough so that it isn't really worth it to wear any armor. Maybe you should get to-hit and damage bonuses while in a wild form?
[This may be more of a polymorph control YANI in general]: Diminishing returns on polymorph time limit that prevent you from reusing the same form(s) over and over and over again.
The critical balance needed is to make polyselfing powerful and awesome to play with and use for typical combat, but simultaneously polyselfing needs enough restrictions that it doesn't just turn into Master Mind Flayer: The Game.
One proposed restriction: you can only turn into monsters you have already encountered, or if that is too lax, into peaceful or tame monsters adjacent to you at the time. The druid should be able to pacify most animalistic monsters to take advantage of this (temporarily?)
The starting pet is a woodchuck (or wolf). Pantheon is probably drawn from Celtic mythology, though hopefully not overlapping with Knights.
Some heavy polymorph / monster / player as monster tweaking is probably required, in the sense that there should, ideally, be valid reasons to exist in any given polymorphable form.
Alchemy
Contributions by FIQ, ais523, jonadab, aosdict, Chris_ANG
NetHack's alchemy system is balanced around the assumption that the player will not hold onto nearly every potion in the game, turn them to water, and polypile them into alchemy ingredients; however, this is not hard to do. Should the player do this, they can amass hundreds of hit points worth of full healing potions, or all the gain ability potions required to max out every stat, or get dozens of potions of holy water.
For most potions in the game, diluting for holy water or alchemizing/polypiling for alchemizing is their ultimate fate, and there are enough potions so that the player never really has to agonize over what to do with a potion. One solution to this would be to make more potions than just acid effective for throwing at monsters.
The color alchemy and gem alchemy patches are unsatisfactory, as is any system that ties alchemy recipes to the random appearance of potions. This is because it makes the game choose at the beginning whether powerful potions can be produced out of junk potions/gems, or out of expensive potions/gems, or not at all; all before the player gets a chance to learn how alchemy will work in this game. It has a large impact on overall strategy that the player can't discover until probably the midgame. At the same time, having hardcoded alchemy rules is unsatisfactory because it's inflexible and carries a heavy spoiler requirement.
Random alchemy is also odd: dipping the same potions in the same way can yield different potion results.

1 + 1 = 2
A radically different system from how alchemy currently works: no matter how many potions are involved in the dipping, only two are consumed, and two alchemized potions produced.

Intended as a balance fix for the player's current ability to make stacks and stacks of full healing, gain ability, or gain level potions, and promote use of found potions instead of diluting them.
Significantly, potions of holy water mostly work like they do now - the holy water does not mix with anything and is consumed, while the dipped item becomes blessed - but you can only dip a singular item into the holy water, including other potions. This loss of the ability to mass-produce holy water creates a significant balance change.
Or it could sometimes make two holy waters, but be biased against it, and allow both waters to become uncursed in the process.
Still unbalanced, since holy water can otherwise be mass produced through water prayers and blessed confused remove curse.
Undiluted potions can be duplicated by dipping them in normal water, e.g. one potion of gain level + one water = 2 diluted potions of gain level.
Diluted potions may need to have weaker effects to compensate for this, or undiluted potions stronger effects.
Or potions in general should become rarer, and possibly generate diluted.
Sink alchemy
Allow sinks to be catalysts for alchemizing things. (Or possibly add a "cauldron" as a new piece of dungeon furniture, but that's iffier.)

You can dip potions into sinks to pour them down the drain, experiencing the vapor effects in a safe way. (Pouring polymorph down the sink of course polymorphs the sink.)
If you don't pour the potion down the drain, you instead mix it with the fluid from the tap, which is usually water but can already be a random potion.
Possibly, doing alchemy in/on a sink is more efficient. There are many possible forms this could take, such as:
Potions not diluting when you mix them.
Reduced or zero chance of an alchemic blast.
You can get results from mixing potions that you can't otherwise (flavor for this is weak, are you... heating them somehow with the hot water?)
New alchemical objects
Flask, holds multiple quaffs of a single potion type (so that holy water can't be mass-created but other potions can)
Mortar and pestle, can grind gems / other things into dust which can be used to make potions
Alembic, can distill potions from things in the dungeon such as corpses.
Recipe books/scrolls, which tell the reader how to create a certain potion through alchemy, and identifies the result potion or even all potions involved.
Alchemy skill
Non-weapon skill that has various effects on alchemy: make alchemical blasts less common (or zero at high skill), and increase the probability that mixing certain potions yields the right result.

Cantrips
Contributions by K2, aosdict, jonadab, ais523
Cantrips are level 0 spells that cost d2 or d3 power to cast. In order not to let them be unbalancing, they don't train skill and are mostly useless, except in certain circumstances or for low-Pw spellcasters who can't do much of the bigger stuff yet. ais523 suggests that good candidates for cantrips might be things that have little combat use, and whose effects could be duplicated by backtracking or other tedious things, but would be useful to avoid boredom. Given their cheapness, they should probably not train skills, and may not even need spell schools. Most ideas for cantrips seem to be a little too powerful and would do better off as normal spells (and are added to this page as YANIs for separate spells); however, those that seem like they would fit are listed here.

Increase the odds of monsters dropping a corpse in the next few turns.
Create an empty unlocked chest. (This would need some restriction so you can't farm and sell them.)
Mark a map square with a symbol, perhaps a comma, that is no different from normal floor but shows up on #overview and the normal map view.
Deal some small damage, such as d5 or d6, to a nearby creature. (Acid Bubble from D&amp;D is a nice corresponding cantrip.)
Dig out a single square.
Create a cancelled hostile yellow light. It cannot explode at you since it is cancelled, so it becomes an autonomous light source of radius 1, which can't follow you down levels like a pet can. Killing it should not grant you any experience; otherwise this would be easily farmable.
Light a radius 2 or 3 area permanently, like a weak form of the spell of light.
Mage hand: you indicate a direction and the nearest item on the floor in that direction, assuming it's under 100 weight or so, is brought to you and is placed in your inventory. This can be used &gt; to get things out of pits.
Create an illusion of yourself at your spot. The illusion never moves. Monsters that see it assume it is you and will attack whichever one is nearer (the illusion is instantly destroyed if attacked).
Monster AI changes
Contributions by jonadab, FIQ, aosdict, flump, mtf, Chris_ANG, xyzyxx, Pavel
Monster intelligence and AI strategies should be much more fleshed out than the current definition of "having hands and neither mindless nor animal". A clear way to do this is to implement different degrees of intelligence or even just an Int stat for monsters, which affects their strategy for doing certain actions like fleeing (do they flee intelligently like monkeys do, or in a random direction?) and using items (a dumb monster might try to read a scroll of fire and burn itself to death).

Smart monster attack strategy
Very intelligent monsters calculate whether it is more advantageous in terms of damaging the enemy versus taking damage themselves to pursue a target in melee, keep a safe distance and attack from range, or flee. Complex solutions would involve the monster storing lots of data about which attacks it has seen its opponents perform; however, this might get memory-intensive and expand save files quite a bit. A possible algorithm that relies only on game state and is based on FIQhack's dragon AI algorithm is as follows:

If able to attack at range (spit/breathe/shoot missiles/use items/etc):
  If the target is in range but not adjacent:
    Attack at range.
  Else if the target is adjacent, and is at least as fast as the monster:
    Attack in melee, or use ranged attacks point blank.
  Otherwise:
    Try to move somewhere aligned with the target, as far away as possible while still being in range.
Else if the monster is unable to attack at range but will be able to soon (dragon):
  Stay out of line with the target.
Otherwise:
   Close to melee range.

Group AI
Monsters that spawn in groups are currently completely individualistic and try nothing more complex than charging towards the player and hitting in melee once they get there. This makes it easy for the player to cheese what would otherwise be tough battles, e.g. by standing in a doorway and killing them one by one, or by kiting them. There are some proposals for smarter AI:

If a single monster in a group is next to the player, try to pull back until allies can get next to the player.
Avoid doorways and narrow corridors; if you are in an open space, stay there unless you decide to move to another open space, and hang back from the doorway where the hero is, forcing them to enter the room in order to pass.
Groups of intelligent monsters also try to stay out of the way of ranged fire if possible.
If the current strategy is to defend a certain area, form ranks to block the player from reaching it.
Pincer maneuvers; some monsters of a group will split up and try to get behind the hero or attack from another side. If the pincering group hasn't gotten in position yet, the other group will fall back until they catch up.
Group "leaders" (loosely defined as a M2_LORD or M2_PRINCE monster in a group of monsters of the same monster class) will try to put the group between them and the player. The presence of a leader could also buff the strategy or intelligence of the group it is in.
Wolf pack: the monster of the class with the highest level, or failing that the highest max HP, "leads" the pack, and all other members key in on this leader and follow it. This means if you get the leader to flee, the rest of the pack will flee as well.
The Yendorian Army can form a phalanx, which is an ordered rectangle of soldiers. Will stick to wide open areas, try to stay out of the range of ranged attacks until they can swarm around you. Enemies forming a phalanx could receive to-hit and AC boosts.
Golem AI
Golem AI/strategy could be selected from a set of possible directives when the monster is created. They follow this directive completely and literally, which may result in some interesting behaviors. The player can #chat to the golem to have it mumble its directive.

Kill all humans - golem attacks the nearest human it can find, not necessarily the player.
Gather gold - golem pathfinds to the nearest gold on the level. If that happens to be carried by a monster, attack it.
Build a castle - golem seeks out boulders and tries to pick them up and pile them into one small collection of spaces on the level. If you destroy or move them, it becomes hostile.
Get corpses - golem tries to collect corpses, but will not hesitate to make more if there aren't any more on the level.
Build more of myself - golem tries to collect the material it's made of. It attaches these to its body, increasing its HP and maximum HP; when its maxHP is high enough, it splits into two golems like a blue jelly.
This would probably require a general AI overhaul.

Miscellaneous strategies
Default: Monster roams aimlessly unless they can see hostiles, in which case they beeline towards those hostiles. Smarter monsters might remember the last place they saw a hostile and beeline towards that square when the hostile goes out of sight.
Lure: Active only when a monster is fleeing and knows about a trap in the vicinity. It tries to get the trap between itself and you.
Blocking: Monster tries to get between the player and a certain space. Won't work well when there's only one of it, but will do nicely in small or large groups.
Zombie resurrection: If zombies can resurrect each other through physical contact, living zombies will try to move towards zombie corpses they can see.
Throw weapon versus wielding it: Mostly useful for things like daggers or knives. Most monsters should be smart enough not to throw away their last melee weapon when they know they can hit for more damage with it. They will, however, unwield weapons and hit you with fists if their only weapon left is grossly unfit for melee (i.e. crossbow).
Darkness: Try not to move out of darkness / into darkness unless there's no other choice. If in the wrong one and doing nothing special, beeline towards the nearest visible way out of it. Most useful for gremlins who want to stay in darkness.
Passwall: if monsters cannot take physical items with them when they phase through walls, they will not actually pass through walls while carrying any items they care about, unless they are fleeing, in which case they will abandon the items.
Food smells: If the hero is carrying a lot of food in open inventory, monster AI may be more effective at tracking the player, depending on if the food is anything the monsters like to eat. Carrying around lots of fleshy food like tripe rations or meatballs helps carnivorous monsters track, carrying around produce helps herbivorous monsters track, tins don't have any scent or effect, inediate pets get no tracking bonus.
Hero displacement: Monsters often attack each other because they think the hero is displaced where another monster is. The smarter a monster is, the more chances it should have to re-roll this displacement roll as long as it keeps landing on other monsters. Or else, if there's only one displaced image, smart monsters should conclude it's not where the other monster is and lash out randomly at empty space.
Bones ghost AI: camp on the bones pile, guarding it, never chase the hero away from it.
Insects returning to the hive: bees periodically path back to their hive unless they're actively chasing or combatting something. Ants do this too, and even pick up and bring back food items.
Swarming AI (bees and possibly other insects): before moving, they calculate if they can see any others of the same monster, and if so, they are disincentivized for moving into a space where they would lose sight of all such monsters. This should keep swarms actually cohesive but still able to move along corridors and pursue the player.
No reason to move: the monster doesn't move, or moves infrequently and randomly, unless it sees you as an enemy. It can have a normal speed and doesn't need to be sleeping or peaceful or anything. If it no longer detects you, it may return to its state of not pursuing you.
Resistances
Contributions by FIQ, aosdict, ais523, jonadab, NeroOneTrueKing
The current resistance system is unsatisfying, because most resistances separate the effects of something into a binary outcome: worse effects with no resistance, ameliorated effects with it. Most resistances also are eat-once-and-be-protected-forever, which is uninteresting in the long term. Proposed solutions to this generally assume that there will be some distinction between resistance and immunity, which offers better (or total) protection but is not normally obtainable as a permanent intrinsic effect. This also enables partial resistances (as found in SporkHack) to be used, though some ideas still treat them as binary - either you have it or you don't. FIQHack recently implemented a form of this.

Possibly extrinsic immunity isn't as good as inherent immunity.
Resistance halves HP damage and cuts attribute loss down to 1 point.
Role benefits should probably only be resistance and not immunity.
For partial resistance, damage is easy enough to do (express your resistance as a percentage and cut damage by that percentage), but many effects, particularly those protected by MR, are binary, and will be tricky to adapt.
Resistances could start at 100% when you get them, but decrease by 1% every time it protects you from something.
Thief stones
Contributions by ais523, aosdict, jonadab
Add a new gray stone, the "thief stone":

It is a magical gray stone that one-way teleports items out of your inventory into a particular square on the level it was generated in.
This works across levels; carrying a thief stone to another level and using it will teleport items to the same square on the original level.
If you pick up the stone while it is unidentified, it will teleport both it and some item back to its spot, and become identified.
The chosen location will be somewhere suitable for stashing: a vault, closet, or any space with a container on it is good.
Barring this, pick any square that is walkable and not specifically unsuitable: the insides of shops, doorways, etc.
An empty chest will be generated on the chosen location if there is not a container already there.
When formally identified, a stone will say "(keyed to branch:dlvl)" where that is the branch and level that it sends items to.
The player can rub it on items or apply it on items to teleport them to the keyed location.
Items that teleport from the stone will go into the topmost container on the keyed location. (The player can put an ice box on there instead if they really want to...)
The stone cannot teleport mundane items, in order not to encourage massive stashing of every item in the game. It will normally only work on treasure and magical items (oc_magic).
Hitting a gold golem with the stone will levelport the golem (and possibly also the stone) to the keyed level. This works on the player too, if polyselfed into a gold golem but not carrying the Amulet.
The stone can be cancelled and become "inactive", which will make it not teleport anything anymore. Possibly, blessed charging re-initializes it.
Beatitude determines what the stone will teleport:
Blessed stones work on all magical items, artifacts, gold and gems (including glass).
Blessed stones also intervene automatically when you would lose gold from a spellbook, leprechaun, throne, fountain, or whatever. The gold will be sent to the stash instead of being removed.
Uncursed works on all magical items but not artifacts, gold or gems.
Cursed works on all the same things uncursed does, but will not work when the player tries to use it intentionally.
Additionally, cursed stones have a 10% chance of activating whenever the player tries to pick something up, sending the item to the keyed location instead.
Attempting to pick up a cursed stone will always teleport it back to the keyed location, regardless of whether it is identified. Unless the player is standing on they keyed location, in which case they may pick it up normally.
Crafting
Contributions by aosdict, ais523, jonadab, mtf, ChrisE

Craftsmen's Guild
Populated with master craftsmen who work on the principle of "valuable junk items + very large sums of gold = desirable items". They can also do some things available to the player, like increasing weapon enchantment, without needing the specific consumables needed for the player to do it.
Would serve as a replacement or stand-in for the black market. Resolves some of the problems with balancing black market shopkeepers: if you kill the black market staff, you can have every item in the market, so black market staff must be insanely powerful. If you kill a master craftsman, however, you don't get anything of value. Therefore, master craftsmen don't have to be insanely powerful, or even good fighters.
Not as good as wishes; there are some things they cannot make for you, like magic lamps, and many magical tools. You cannot specify enchantment or blessing either. For items for which enchantment doesn't matter, the material cost will be higher.
The interface works by #chatting to them. They will ask you what you want to create, and you enter it (using the wish parser logic to extract the proper object class), and then they will tell you the items and gold they will need for it. These could either be randomized or use certain fixed ingredients with some randomization or use completely fixed recipes; if randomized it will be deterministic for that item for that craftsman in that game. You are then prompted to select the items from your inventory.
For gold and other balance reasons, this would probably work better the farther it is into the game; maybe it could even be found deep into Gehennom. Maybe you even have to liberate it from a demon lord.
Craftsmen might include:
Metalworkers (see below)
Wandmakers (produce wands)
Scribes (produce scrolls and spellbooks)
Alchemists (produce potions)
Toolsmiths (produce mundane and some magical tools)
Jewelers (produce rings and amulets)
Sculptor (produce statues and figurines)
Leatherworkers (produce leather items and saddles)
Chefs (produce food)
Arcanologists (transfer charges/enchantments from one item into another, consumes only gold and not items)
Metalworking
Probably the most important sort of craftsman for many characters. There could be multiple types, each specializing in one type of metal, or just one type that does everything.

Silvering items (or gilding, or copper-coating) should require you to use up junk silver items equal to some amount of weight proportional to the weight of the new item. The zorkmid cost of silvering should be very high.
A forge room type (probably containing lava and maybe some junk items like iron chains) could be added which has one or more smiths in it (silversmiths, goldsmiths, blacksmiths).
Goldsmiths seem rather pointless right now, since there is only one gold item (the ring). They would be more useful if gold equipment existed and conferred some benefit.
Blacksmiths don't have much to do as far as turning items into iron goes, but they could produce iron weapons of a type the player wants, or repair and improve iron weapons and armor (increasing its enchantment).
Player crafting
ais523 has pointed out that if there's a craftsmen's guild or even scattered craftsmen, the process of traveling back and forth to and from it might become busywork. So if players could craft things on their own, that might be better.

Would probably need properly flavored terrain for workstations, like a furnace or smelter, for certain crafts, otherwise flavor is too weird.
Fixed, non-simple recipes (e.g. existing scroll crafting is a simple recipe) are a heavy spoiler tax and should be avoided.
This could be simple for certain types of items, as in requiring some silver or gold and a diamond to craft a diamond ring, but doesn't explain where any magical effects come from, and also might weirdly tie crafting recipes to randomized appearances which have previously been meaningless.
Probably requires a few more "base" crafting materials, some source of leather, some source of wood, etc.
Corpses could decay into bones, which disappear themselves with a longer timeout, but in the meantime can be used to craft bone stuff
Trap scaling
Contributions by aosdict, mtf, jonadab, FIQ, ais523, Chris, rumflump, firemonkey
Traps don't scale very much (floor traps' having minimum dungeon levels for random generation is about it), and this hurts their balance. Since a trap will have the same flat effect in all situations, it tends to become unthreatening to a player sooner or later, and then having it appear in the rest of the game is pointless. Conversely, some trap effects are too deadly to early characters. In Gehennom, the traps have probably literally been designed by demons, yet the only difference between Gehennom and the rest of the dungeon is the existence of fire traps.

Floor traps
Magic traps' blinding and summoning monsters effects should be split up, since both at once tends to make them much more fatal, especially to early players.
Perhaps magic traps' summoned monsters should be generated with a reduced difficulty.
Statue traps' summoned monsters should be generated with an increased difficulty. +5 was proposed for this, but this may be too high.
Falling rock traps can dump multiple rocks onto you at once, up to (depth/4). Damage is taken for each rock. If a trap would drop 4 or more rocks on you, it may instead drop (rocks/4) boulders on your head instead. Helms should be less effective at reducing damage from falling rocks, and almost useless at reducing damage from falling houlders.
Pits get deeper, which makes them deal more damage, might cause wounded legs with a chance that increases with depth, and take longer to escape from (or are so deep you can't climb out at all).
Rust traps might target your pack instead of your armor or gear. Probably should be renamed to "water trap". On deeper levels, when the game would generate a rust trap, it has an increasing chance of replacing it with an acid trap. These deal corrosion and acid damage (and quite a bit of it, like having multiple potions of acid dumped on your head).
Traps could trigger based on your weight. This makes the trap more likely to trigger on a heavily armored character or one who has collected a lot of loot. Would work nicely in the Gnomish Mines, since gnomes are light and don't tend to carry much stuff. Certain traps could also trigger to a lesser degree if you weigh enough to trigger it but not a whole ton.
Anti-magic fields in Gehennom can attempt to cancel you or your gear. (Would work better in something like FIQHack where there's a cancelled status effect).
Container traps
Container traps' effects also scale based on dungeon level (ideally on the level a container generated, not on the current level, so a player can't levelport a chest up to level 1 and cheese the trap.)
In addition to adding some more effects, also add some effects which cosmetically are the same as other ones, but are more or less damaging. This would, however, make untrapping containers even more useless than it is now; perhaps a trap should stay armed even after you set it off. Another idea is to give certain traps an arming item, like a potion of oil for the fire effect and a land mine for the explosion effect. Successfully untrapping it will deposit the arming item into the container.
Also, make container traps independent of Luck, because currently they encourage the player to ignore containers until Luck is maximized.
Unsorted new trap ideas:

A hand wielding a cream pie comes out and pies you in the face. Untrapping this will drop the cream pie into the container's inventory.
Door traps
Instead of making all trapped doors explode and stun the player, add more varied door traps. The trap should be determined based on depth. It should also be selected deterministically based on the coordinates of the door (a convenience so that a trapped door will always have the same trap effect without having to store which trap it is.)
Additionally, new traps can also be used with more door states, rather than have all traps trigger by trying to open the door. Nondestructive traps could also remain on the door until the door is untrapped, rather than vanishing.
An interesting addition would be if doors were made restrictedly or completely untrappable, in order to prevent optimal strategy from being attempting to #untrap every door that the player comes across. Or possibly an attempt to open or close a door should do a cursory trap check.

Trap effect
Trigger
Persists
Minimum DL

Hinges screech loudly, waking nearby monsters.

Opening or closing
Yes
1

Closes and locks itself.

Opening, closing, or stepping off the square
No
1

Electric shock from the knob, dealing 1d(DL*2) damage, that doesn't destroy items.

Opening or closing
Yes
2

Bucket of water falls on your head and causes water damage to several items in inventory.

Opening or destroying
No
3

Your hand is stuck to the knob, causing you to be unable to move for the next few turns.

Opening or closing
Yes
3

Hingeless door: either falls on top of you and deals 1d(DL/2) damage, or (more likely) falls the other way and you fall over on top of it. Either way, you are stunned for a few turns. The door becomes D_BROKEN.

Opening
No
6

A boxing glove swings out from behind the door and punches you, dealing damage and causing you to stagger/hurtle back a few steps.

Opening or destroying
No
8

Object falls out of the ceiling on the player's head (copying an ADOM trap).

Opening or destroying
No
10

Knob burns your hand for 1d(DL) damage and causes you to drop your weapon. Gloves reduce damage and prevent the drop.

Opening or closing
Yes
12

Door that explodes in a fireball: possibly no stunning, but burns inventory as it does in GruntHack.

Opening
No
15

Magic traps
Based on the idea that magic trap effects specifically should scale based on level. Proposal by FIQ.

Effect
Dungeon level or branch

Magical explosion: HP damage, Pw increased to full, maxPw increase
Any (with fixed 25% chance)

Odd feeling (using standard odd feeling messages, no effect)
Any (with fixed 25% chance)

Grateful djinni, wish
1 (with fixed 5% chance)

Remove curse (like uncursed scroll)
Outside Gehennom

Curse items (like harassment)
Within Gehennom

Horizontal teleport
1-6

Blinds for 1d5+10 turns
3-8

Hostile magic whistle; summons monsters that already exist on the level to appear around the player
5-10

Gain 1 charisma and charm surrounding monsters
7-12

Create a stinking cloud on the space
9-14

Polymorph
11-16

Randomly bless and curse inventory (like confused blessed remove curse)
13-18

Do both the blinding and hostile whistling effects above
15-20

Level teleport
17-22

Surround the player with Z that are buffed by having intrinsic monster detection, being blinded so Elbereth won't work, and being hasted
19+

Surround the player with &amp; that are buffed in the same way
Gehennom

Surround with nasties (like harassment)
Gehennom

Surround with nasties that are buffed as above.
Gehennom

Terrain
Contributions by aosdict, AmyBSOD, bug_sniper, jonadab, NeroOneTrueKing, statuesurfer, FIQ, stenno, Chris_ANG
Fire terrain
Fire terrain is a square that is on fire. It displays as an .. (Depending on how nasty this will be to non-color players, the glyph should perhaps be changed.)

Fire terrain has a certain amount of burning wood material on it.
Standing next to or on fire terrain grants cold resistance, but standing on top of fire terrain has the same effect as a fire trap whenever you end your turn on it.
The fire eventually burns out and reverts to normal floor, the duration determined by the total weight of the burning objects.
Killing a wood golem with fire or burning more than a certain weight of objects on a square creates fire terrain on that space.
Throwing burnables onto a fire trap may make them spontaneously combust and produce fire terrain.
Fire terrain can be used to cook corpses.
You can create fire terrain by applying a lit candle to a space with burnables on it
You can also create it by applying a tinderbox to a space, which is a chargeable non-magical tool. Archeologists and Rangers start with one.
Fires provide a light source of radius 3, but cannot be moved. Monster AI will not travel over fire if the monster is not resistant.
Air terrain
Extend air terrain to be used outside the Plane of Air, representing a chasm or abyss. If you step on air without levitation or flying, you fall to your death ("killed by gravity"), unless you're on the Plane of Air (where there's no place to fall to). The obvious glyph is   but wouldn't work because players are used to thinking of it as rock; other possibilities are ~ or #, or giving the player a warning when they would be stepping out into open air. Alternatively, don't let the player move into air terrain unless they confirm it.
Grass terrain
Ideas for making grass terrain (. or ,) be an interesting piece of terrain:

Dies and turns to normal floor if hit by fire or have a death ray zapped over it
Turns into fire terrain if hit by fire and can spread to nearby grass
You can plant trees on them, whereas you cannot do this on normal floor.
Other new terrain types
A new type of "fence" terrain that is like wooden iron bars: it cannot normally be moved onto but it can be burnt or kicked down, and it does not block line of sight.
Slope terrain, which is a terrain that appears like walls but does not block line-of-sight. It blocks movement unless levitating or flying, and cannot be dug down on or into. If you somehow get onto slope terrain (such as by stopping levitation while on it), you can move off it in any unblocked direction. This would allow interesting level designs like pyramids and switchbacks. Is still a bit problematic, since for things like a large pyramid, you would be able to see straight over the top of the pyramid and down the back side.
Changing terrain glyphs
Primarily to reduce overcrowding of #:

Iron bars and fences render as cyan/brown |-.
Sinks render as \ (color unspecified, could be blue).
Closed drawbridges render as some color of + which is not currently used by terrain - perhaps red or orange.
Corridors could be moved to . but this would probably be very unpopular and make levels look a lot worse.
Trees could be +, or possibly \ to avoid spellbook confusion.
Clouds could set the background color of a space and not change the foreground color, and could possibly be rendered with a blank space character, but this would probably have issues on non-color terminals.

List of shorter YANIs

Idea

Variant(s)

Source

Monks, or anyone skilled in martial arts, can kick weapons out of an enemy's hand

Tarmunora, NeroOneTrueKing

Dragon scales can be enchanted into dragonhide gear that is not scale mail

GruntHack

Demo

The Watch start with a small amount of gold, and will throw it at a player of the opposite gender while the player is disrobing

Demo, Grasshopper

Engraving with Fire Brand burns the engraving as a wand of fire does.

Tarmunora

New headstone messages:
I'll just hit this thing a couple more times, it'll die.
I don't need to unburden myself, they're only soldiers, I've been killing soldiers, it'll be fine.
Maybe if I press this key a bit harder I'll hit for more damage next time.

Chris_ANG, jonadab, Grasshopper

Blank spellbooks in flooded libraries generate with the "number of times read" counter full, so they can't be polypiled into readable books.

dNetHack

NeroOneTrueKing

Add a high level monster spell "raise dead", which resurrects nearby corpses as hostile monsters.

Grasshopper

When attacking into a pit or falling while fumbling and wielding a pointy weapon, you have a chance to fall on your weapon.

bezaban

Boots of shock resistance, which have a thick rubber sole to prevent you from being grounded.
Note: several other people have commented that since such boots would prevent you from being grounded, you would actually take extra shock damage from other things, like touching grounded metal objects.

Grasshopper

Scroll of detect magic shows magic fountains on the level as well as magical items. Fountains discovered this way are then displayed as "magic fountain" when near or farlooked. Wizards can see them as magic fountains already without needing to detect magic.

GruntHack

aosdict

New monster: green cube, which combines the abilities of a green slime and gelatinous cube: both sliming and paralysis.

Grasshopper

Merge the P and b monster classes, on the grounds that puddings and blobs are both classes of amorphous monsters that are sparsely populated. This was followed by a long discussion with several people about monster class rearrangement in NetHack Fourk.

jonadab, Grasshopper, bug_sniper, aosdict, Tarmunora, FIQ

Necromancer patch / necromancer class added to dNetHack, including: creating skeleton armies, binding the undead via rituals similar to the Binder, launching rocks that contain small petrified animals that transform into undead animals, bone chains, encrusting undead minions with different jewels to grant them different powers

dNetHack

introsp3ctive, Demo

Opening a cursed bag of holding does not tell you what has disappeared, or it just says "Things have disappeared from the bag!" without describing them

AmyBSOD

Role whose quest artifact's base item is a helm of opposite alignment. (This is apparently in SLASH'EM Extended, but so are probably half the things on this list and I'm not going to bother cross-checking everything.)

jonadab

Conflict affects things in a radius. The ring of conflict is a chargeable item, affecting this radius. Wearing multiple rings of conflict stacks the effects.

jonadab

Monster status "discord", which causes a monster to be seen as a target and be attacked by other enemies. On the player, discord is the same as wielding Stormbringer. Discord is available through the spellbook of discord.

Fourk

jonadab

Applying a stethoscope tells the target's gender, and the hunger status of pets.

Grasshopper

Easter eggs as an actual item, in addition to monster and chicken eggs.

Grasshopper

The Bell of Opening is carried by your quest leader, who gives it to you when you return to them with the quest artifact. This solves the problem of making a game unwinnable by permanently changing alignment, since you can also get it by killing the quest leader. Should the leader leave the level (by levelporting down, for example), they are considered derelict of duty and the player can start the quest.

jonadab, Grasshopper

Leprechauns steal anything made of gold, in addition to plain gold pieces. (In vanilla, the only gold item is the gold ring, but variants have other gold items.)

FIQ

Add rumors to FIQHack that warn about dragons, which can be fairly dangerous.

FIQHack

flump

More acid resistance sources in FIQHack, to balance yellow dragons' exploding acid breath. Possibly a ring or amulet of acid resistance.

FIQHack

ais523, FIQ, flump

Asmodeus should wield an artifact called the Ruby Rod.

dNetHack

zombifier

Pets on the Astral Plane always go with you when you ascend, regardless of whether they're adjacent or leashed to you.

AmyBSOD

Roditaur: new humanoid monster that has an oversized rat's head and four arms. Has a powerful bite attack and four weapon attacks.

SLASH'EM Extended

jonadab

Add "numeric prefix", "microcode bug", "aklys bug", "bobble hat" and "puzzle fiend" as hallucinatory monsters.

ChrisE, raisse, ais523

Gehennom should be half as long, 10-12 levels, and should be mostly or all unique levels that are randomly chosen from a larger set

Duam

Oilskin cloaks should be MC3 instead of MC2.

jmr

Dragon eggs can be used as special types of thrown missiles. Black dragon eggs specifically have a disintegration effect.

Wooble

Level sounds on every level with a branch stairs. For spoiled players, the main benefit of this is to help locate the stairs to Vlad's Tower.

aosdict, jonadab

Chicken eggs identify as such when you formally ID them, and all eggs of a known type stay identified for the rest of the game.

Grasshopper, jonadab, nooodle

Gauntlets and boots of reflection

Tangles

Water walking boots protect inventory from water and protect against drowning attacks

jonadab

The timeouts for intrinsic invisibility and see invisible from eating a stalker corpse should be very long.

SporkHack

jonadab

See invisible operates on a scale that determines what level of invisible monsters the player is allowed to see. (A low-level monster that drinks a potion of invisibility should be visible even with weak see invisible, an arch-lich casting disappear should require very strong see invisible.) Invisibility should do this too and have a scale as well (one notable place on the scale being that invisibility is kept only until the invisible thing takes an offensive action). If rings of invisibility and see invisible are made chargeable, this is an obvious avenue for them.

NeroOneTrueKing, greqrg

Asmodeus and Baalzebub demand gold proportional to their difficulty or monster level, not the player's wallet. Possibly, if the player does not pay, they remain on the downstairs and will not move until the player has paid, which allows the player to return with the requisite amount of gold.

jonadab, zombifier, aosdict

Several small spellbook additions:
The thick spellbook weighs more than other kinds. The thin spellbook weighs less.
Reading a dusty spellbook has a chance of making you sneeze (if you are in a form with a nose), which wakes up monsters.
Reading a silvery spellbook as a silver-hater makes you "not able to handle" the book and drop it

aosdict, raisse

Instead of pushing pets out of the way as they do other monsters, the Riders can trample over pets, instakilling them.

AmyBSOD

Net gnomes - wield tridents and have a sticky attack (the net), which causes subsequent attacks to hit automatically

Grasshopper

Players can polymorph dungeon features by zapping a polymorph beam down at it, with some special cases:
Headstones can be created by polymorph and are more likely than other outcomes, but cannot be polymorphed into anything else. Trying to do so only polymorphs its epitaph.
Polymorphing an altar angers that altar's god and any attendant priest since you effectively destroyed their altar
Fountains either cannot polymorph into anything besides headstones or have a very limited chance of becoming something else; this is to prevent the player from being able to generate a bunch of thrones from fountains.

raisse, aosdict, jonadab, AmyBSOD

You can wear an empty bag over your head to blind yourself, but this sets charisma to 6. If you wear an oilskin sack on your head, it starts a strangulation timer. If you wear a bag of tricks on your head, you get YAFM and instadeath, or possibly it just constantly bites your head.

Grasshopper

When invisibility is about to time out, give the player a warning message "You thought you saw yourself for a moment" ("You seem to unfade for a moment" if you can see invisible, "You feel introspective for a moment" if hallucinating.

raisse, aosdict

Merge the ring of hunger and the ring of slow digestion into the same item; one is it with a positive enchantment and the other is with a negative enchantment

jonadab

Untrapping a lavender trap gets you potions of lavender essential oil. Ants naturally dislike lavender oil, so ants will flee from a player that has been sprayed by a lavender trap or used a potion of lavender oil.

SLASH'EM Extended

aosdict

Uranium wands glow in the dark.

Grasshopper

Special room "ruined church" that contains ghosts, pieces of glass scattered around the floor, maybe an altar, maybe a spellbook, and blank paper/scrolls of junk mail scattered around the floor

rdplatypus, aosdict

Bump the cloak of displacement up to MC 2.

rdplatypus

Add a conduct for tracking whether the player has not used any of each class of objects.

AmyBSOD

Tripe rations should not generate randomly very often, but they should appear in the inventories of monsters that like tripe, such as orcs.

jonadab

Luck's effect on whether a projectile breaks is nerfed. Instead, the enchantment is the primary factor, and is not just simply "+2 or above".

AmyBSOD

Polymorphing a highly enchanted object will vaporize it if it turns into something that normally can't be enchanted that high.

AmyBSOD

Any gaze attack which is prevented by blindness (one which is visual in nature) is prevented by hallucination, or at least the effects are reduced or mitigated. Possibly archons' blinding gaze should be exempted from this, with the hallucinatory message being "The power of the Aurora overwhelms you!"

FIQ, Chris_ANG, aosdict

Give monsters their own XP, because the system of "all kills are equal experience" is weird

FIQ, greqrg

While wielding a polearm and attempting to move in a direction where there is a monster 2 spaces away, attack with the polearm instead of moving. Also attempt an attack for monsters 2 spaces away diagonally if polearms are Expert. To hit a monster a knight's move away, it still has to be applied. If preceded by the M key, don't try to attack.

FIQ

Make the Ranger quest artifact a crossbow if you are a gnome.

K2

Limit the amount of tamed monsters you can have at once.

FIQHack

FIQ

Rust monsters and disenchanters are quadrupeds, and should be q. (This would leave R empty though.)

jonadab

Add some effect to Snickersnee so that it's not just a slightly better katana. Ideas include confusion resistance, stunning resistance, displacement.

K2, jonadab, Mandevil

Buff late-game undead, because undead's significance in Gehennom tends to be pointless since they aren't scary by the time the adventurer gets there.
Zombies can resurrect in Gehennom akin to GruntHack zombies.
Spectres, which are like wraiths but much faster and with more attacks.
Vampire mages.
Skeletal dragons.
Minotaur zombies.
Z might need to be made ungenocideable.
GruntHack-like zombies, which inflict zombification sickness and eat your brain to drain Int.
Shades can generate in graveyards in Gehennom.

jonadab, aosdict

Gnomes get a racial bonus using aklys and crossbow. Should probably be done by affiliating an item type with a certain race, adding this as a new object attribute, and only specifying it on racial items (elven armor, orcish weapons, the aklys and crossbow, etc.)

jonadab, aosdict

A skill system with more intermediate levels, such as Unskilled -&gt; Basic -&gt; Competent -&gt; Skilled -&gt; Advanced -&gt; Expert -&gt; Master -&gt; Grand Master.

jonadab

Most artifacts should have a negative to-hit bonus, so you have to train the weapon's skill with some weapon that isn't the artifact.

jonadab

Monsters get bonus AC against attacks coming from allies (hostile versus hostile, or pet versus pet).

Chris_ANG

Roles which are good with melee weapons (Bar, Val, Kni?, Cav?) should be able to see the enchantment of their weapon after using it for a while, or perhaps right when wielding it. Alternatively, seeing the enchantment of a weapon should be based on skill: basic will reveal enchantment on 1% of hits, skilled on 10%, expert as soon as you wield the weapon.

Chris_ANG, FIQ

Have the game display your base to-hit bonus (presumably excluding circumstantial modifiers) at all times, perhaps for both ranged and melee to-hit.

Chris_ANG

Allow the player to disable things that display on the status lines, like ability scores, gold, dungeon level, and experience level, none of which have to be monitored constantly like HP or Pw do.

Chris_ANG

Bull rush command that lets a player shove a target monster back one or more squares. The relative size of the monster and player and the strength of the player are important factors. The character might move into the space of the displaced target.

Chris_ANG

Split up the effects of magic resistance, as it is too extensive. It protects against magical force, death magic, teleportation, polymorph, etc.
Death resistance conferred by a helm, an amulet, maaaaaybe as an intrinsic gained through crowning

jonadab, FIQ

Maximum HP should have some ceiling that depends on your race/role combination, proportional to what you would get by leveling up to 30 as that race/role.

Chris_ANG

A way to search for hidden passages behind a boulder you are pushing.

loli

A role whose starting pet, if eaten, confers amazingly good benefits, so that the player has to make a hard choice of whether to deliberately kill and eat their pet, and suffer the penalties.

SLASH'EM Extended

aosdict

Artifact arrow that auto-returns to your pack and cannot break. But there is only one of it, so it can't be multishot.

bug_sniper

A way to transfer contents from one container to another without moving through your inventory.

bug_sniper

A number of ways for weapon enchantment to be learned without formal identification.
Rubbing it on a blessed touchstone
Making a number of successful hits with it
SLASH'EM's weapon practice ability
Making a number of attempted hits with it (they don't have to hit)

Tarmunora, aosdict, jonathanhanes

Wind dragons, a cyan D whose breath is a wind beam: it doesn't damage you, but blows you backward, and can't be reflected. Their scales grant flight, which now confers resistance against knockback and Newton's Third Law.

Tarmunora, aosdict, jonadab

Some roles get food appraisal as a permanent intrinsic. Caveman at level 6, Tourist at level 10, maybe Healers at level 1 but they already get poison resistance so maybe not.

aosdict, raisse

In Orcish Town, have a powered-up hostile orc shaman who has taken over from the dead Minetown priest.

K2

Dwarf kings have a chance to carry a silver dagger.

raisse

Lightning attacks deal more damage to monsters in water.

AmyBSOD

Cavemen get a berserking bonus if their pet gets killed.

tesko

A side effect of a ring of three wishes: while wearing it, if you die, a wish gets used up and you get lifesaved.

dnethack

NeroOneTrueKing

You can #invoke a ring of hunger to make yourself more hungry immediately so you can eat dragon or giant corpses.

bug_sniper

You can apply an amulet of strangulation to an adjacent monster (that has a head and neck) which will strangle it in 5 turns.

bug_sniper

Magnet traps that attract metal items out of your inventory, but also attract loadstones and are a means of getting rid of them.

bug_sniper

Applying heat to loadstones demagnetizes them and turns them into flint stones.

bug_sniper

The effectiveness of the protection spell depends on how your off-hand is being used (open is better than carrying a shield, which is better than using it to wield a weapon). If your off-hand is free, the spell gives you a "spectral shield".

NeroOneTrueKing

Amulets can be flushed down toilets to identify them.

SLASH'EM

bug_sniper

The game should allow you to reread a spellbook and relearn the spell whenever you want. The prompt should be "You know 

<spell> quite well already. Read the book anyway? (yn)"

ChrisE, AmyBSOD

MSGTYPE:replace to replace a specified message with another one.

stenno

A monster that stands helpless if you can see it with normal vision (not infravision, or telepathy, or detect monsters or anything else), and attacks viciously if you cannot.

jonadab

Blessing a corpse prevents it from being tainted or (ordinarily) rotten (the "Blecch! Rotten food!" effect).

ais523

Greed as an object property for containers: the container will refuse to open 80% of the time, costing a turn. Either any gold put into the container vanishes permanently or gold weighs nothing when in the container.

FIQhack

FIQ, jonadab

Archeologists should start with searching rather than having to get to XL 10 for it. To compensate, they now get stealth at XL 10 instead of 1.

hothraxxa

Searching finds everything in your range, but takes multiple turns. The s command by default will take this many turns and will either tell you about all the hidden things around you or tell you that there is nothing interesting; you can specify a numeric prefix to search for less than that if you want.

jonadab

Amulet of zombification. Increases your zombification counter while you are wearing it. Taking it off cures the zombification.

FIQhack

jonadab

You can jump over swimming monsters in water, and over tiny monsters.

ais523, raisse

Your starting cat can have kittens.

Wooble

The helm of opposite alignment may turn lawful or chaotic characters neutral, instead of always converting to lawful or chaotic.

xyzyxx

Armor should make use of its corpsenm (monster index) for efficiency and to do interesting things that are not currently done. For example, this would allow dragon scales and scale mail to be merged into two items that use the various dragon monster indexes to figure out its special effects, and it would allow for fireproof low boots created from polypiling a crocodile corpse to be flavored differently. In variants where applying dragon properties to other pieces of armor is being considered or planned, this would provide an easy way to do so.

ais523, FIQ

The preparation method of tins should be deterministic, so that tins that stack together will have the same method.

jonadab

Add shallow water to the Gnomish Mines (not GruntHack's deep water).

Fourk

FIQ

Move enchant armor/weapon scrolls to the 200-zorkmid tier.

FIQ

Some version of key breaking, perhaps when trying to use a cursed key. However, this should not go the SLASH'EM route of allowing any unlocking device to break, since that just makes the player carry around extra keys. Skeleton keys should be made of bone and can break. Perhaps add a new key that is not breakable but is rarer than skeleton keys (stealing some of skeleton keys' probability).

jonadab, FIQ

Stethoscopes and probing on a pet shows when that pet is satiated.

GruntHack

aosdict

Stealing from shops via your pet doesn't directly anger the shopkeeper, but the shopkeeper is aware of it and raises their prices to compensate and eventually won't let you reenter the shop. Alternatively, the shopkeeper simply will block the entrance as long as any monster in the shop is carrying unpaid items, but this could be circumvented with a magic whistle.

FIQ, jonadab

Add a dogcatcher, who will come and impound your pet if it misbehaves (stealing from shops, killing Minetown citizens)  and you don't get it leashed before a certain amount of time has passed.

jonadab, aosdict

Grandmaster skill in martial arts allows you to shatter enemy weapons like two-handed weapons do.

K2

Add a silvery potion, either as a random appearance or a dedicated potion like dNetHack's potion of silver starlight, which will silver ammunition dipped into it, perhaps temporarily. It might also silver other weapons (spears, daggers) or other items. Random appearances have the possible problems of the potion potentially having a defined dip effect already (polymorph, for example), and it potentially not appearing in the game if there are extra random appearances. Dipping fragile silver items, like silver arrows, into a potion of acid could create a silvery potion.

ais523, aosdict, NeroOneTrueKing, FIQ

Silver weapons should be rarer than they currently are outside Gehennom and fairly common inside it.

ais523, jonadab

Make T-shirt messages not depend only on the object id, so that two shirts generated shortly after one another don't have predictable messages.

AmyBSOD

80% of locks on containers, determined by the object id of those containers, can't be opened by a credit card because they're a latch or padlock or something that can't be jimmied open. Perhaps Tourists get a bonus that allows them to open more locks.

aosdict, jonadab

NetHack4 impossible() should not imply that the save file is corrupted, and the distinction between impossible() and panic() should be less blurry.

NetHack4

AmyBSOD, FIQ

Change the impossible() message (in NetHack 3.x and variants) so that it doesn't imply the user should quit the program (thus destroying their save file).

FIQ

Moving in Sokoban by jumping and hurtling from an iron ball doesn't actually work to bypass boulders in 3.6, so it shouldn't incur a Luck penalty.

AmyBSOD

You can wish for object properties in FIQhack, but only on items that aren't inherently magical.

FIQhack

aosdict

Throwing a cockatrice corpse into water turns it into a hard floor, or possibly ice, with the corpse buried in the new floor.

bug_sniper, jonadab

Blessed potions of gain ability allow you to choose which stat to increase. Possibly, since this would ordinarily be a nerf, max that stat or give you a few points in it.

jonadab

Fumble boots cause you to toss and turn in your sleep if you are sleeping, making you wake up sooner.

bug_sniper

Conflict removes murder penalties since you acted in self-defense.

bug_sniper

Carried loadstones prevent knockback, including Newton's Third Law effects. Possibly it prevents levitation entirely.

jonadab, Tarmunora

Tourists should be able to swim. Alternatively, tourists should specifically NOT be able to swim, but other roles might.

FIQ, aosdict

Mind flayers seek out your pets to eat their brains and turn them into thralls, which makes them effectively a pet of the mind flayer instead.

aosdict

Whenever a player is killed by a mind flayer, they become a thrall in their bones file. In FIQhack, this means they leave an active hostile player monster in the bones with 100% chance instead of 33%.

FIQhack

aosdict

Barbed orcs, which are more deadly than regular orcs.

Andrio

Many different thoughts centered around creating a bard role with distinct and useful gameplay:
The bard and healer cannot both be focused around petmongering, so one of them would have to change. Most likely the healer, as the bard's traditional abilities are only good on pets.
Instead of the standard little dog or kitten, the bard starts with a "party" of 3-4 player monsters, who are randomly chosen from other roles.
This would make the primary strategy focused on having the party do the fighting for you, letting them level up, providing them with weapons and equipment, and not letting them die.
Healers and archeologists, and possibly tourists, don't make very good additions to the party, and so should perhaps be ineligible.
Party roles could be randomly chosen from distinct sets of "strong melee fighter" (Bar or Cav or Kni or Val), "ranged combat" (Ran or Rog or Sam or possibly Tou), and "spellcaster/cleric" (possibly Hea or Mon or Pri or Wiz).
The party will not start with the full starting inventory of their respective roles. They will generally have the same weapons and armor, but will probably not have any of the scrolls, rings, wands they normally start with, and starting spellbooks should be either eliminated or unrandomized.
YASI: the bard quest artifact gives party members the effects of their own quest artifacts.
Healer strategy should shift away from petmongering - the easiest way to do this is change the protection formula in such a way that the protection racket doesn't exist; so that the player isn't incentivized to keep XL as low as possible until they can buy protection.
Difficult for Healers to find a new niche. (Avoidance of combat is an option, but the Class Overhaul proposal calls for Archeologists to fill that niche). Perhaps something that focuses on pacifying monsters by healing them, but this has issues: you shouldn't be able to tame by healing since that turns Healers back in the direction of acquiring lots of pets, and most monsters start at full HP and don't need any healing.
Bards (and probably all players) should be able to equip their pets by #looting them, or a similar mechanism. (This would also apply to mounts.) Intelligent monsters will prefer player-given items above all others and will never willingly replace them for other gear. Possibly make this behavior dependent on options, because some players may want their pets to be pragmatic in their gear choices.
Player monster pets should perhaps not be able to detect curses.
Songbooks, + class items which contain a song that the bard can learn.
Balancing the songbook generation rate against spellbooks might be tricky, because although bards can still cast spells and other roles can play songs, each is not very likely to have that much use for the other set of books. Hardcoding different probabilities based on whether the character is a bard or not doesn't seem very clean.
Possibly the bard should be able to discover songs by trial and error, although simple brute forcing is definitely not the way to do it. Maybe all spellbooks start identified.
The bard could need to practice the song by using the songbook in order to restore "song memory". Song memory does not work quite like spell memory, it works essentially like direct success rate. There might be some mandatory delay between practices, meaning you can't take an unlearned song and practice it up to 100% immediately. Or there could be a possible failure of practice, maybe a dexterity penalty ("Dumb move! You strain your fingers.") to serve to prevent practice-spam. Playing a song would serve to
Spellbooks do not eventually go blank, and can be used for practice indefinitely.

aosdict, FIQ, jonadab, ais523

Player monsters should always resist conflict.

FIQ

If the metal spellcasting penalty were to be removed entirely for one armor slot, it should be the boots slot.

aosdict

Sphere conjurer: a monster who creates hostile spheres.

FIQ

Dragon with slowing breath. The effect stacks with previous effects of slowing breath.

jonadab

Remove instances of "bad RNG" contributing to forms of instadeath or a disproportionate bad effect for a RNG decision made mostly or completely independently of the player's decisions, because they just add randomness or variance to the outcome of the game:
Poison instadeath
GWTWOD
Chameleons turning into out-of-difficulty monsters the player can't handle

stenno

Add spell of summon pets, a level 2 or 3 matter spell that duplicates the effects of a magic whistle. The name needs work.

aosdict, K2

A "morale" stat which replaces charisma, and decreases when you die and get lifesaved, eat terrible food, and so on, but it needs effects other than making you lose the will to go on if it gets low enough.

jonadab

Getting lifesaved has permanent detrimental effects. Perhaps it reduces the stat maximum for an attribute as well as the attribute's current value, like Wis or Con (Con is preferred, because it hits both carrying capacity and regeneration), and if the attribute it would reduce is 3 or below, life saving does not work at all. It could also possibly drain 1d3+1 levels.

aosdict, jonadab, FIQ, K2

Getting lifesaved gives you experience points (because it's a near-death experience).

jonadab

Bards as a monster, who spawn in a group of same-race monsters with a (sometimes but not usually) magical instrument, and they keep their distance and play songs to buff their allies.

FIQ

The Watch should turn hostile when you apply a cursed tin whistle within earshot of them.

FIQ

If you die with zero points, end-of-game enlightenment says "You were a noob."

SLASH'EM Extended

aosdict

Disintegration blasts don't reflect from a wall; they dig it out instead. If the wall is undiggable, the ray merely stops - it never reflects.

FIQ, jonadab

You can #loot trees to get less fruit than you might by kicking it, but the chance of getting bees is much reduced. This might fail, in which case you might fall out of the tree and abuse Dexterity or something similar. If polymorphed into a Y, it has a 100% chance of success; if a human or elf, probably 80%; if an orc, 40-50%; if a gnome or a dwarf, 1-5%.

aosdict, jonadab

The list of monsters that ignore Elbereth should be increased, but the list of monsters that ignore scare monster should remain the same or decrease (3.6.0 Quest nemeses excepted). Perhaps scare monster should be renamed to "scare creature", as it scares humans and elves, which are not really monsters.

FIQ, jonadab, bhaak

Gold generated from monster inventories should be tracked by the game and tail off after a while.

jonadab

Reduce the amount of gold generated on the floor, and probably also that buried under the floor and in rock so it doesn't incentivize the player digging out a level. This is an attempt at gold rebalance.

Elronnd

Quest artifacts, and probably all artifacts, blast other monsters when they enter their inventory, subject to the same checks and chances as the player (however, the artifact will never evade their grasp). This is most likely to be observed when the Quest nemesis or the Wizard of Yendor steals a Quest artifact from the player.

jeremiahL

A colorless or colorblind conduct, settable with OPTIONS=colorblind or something similar at the start of the game, as a permanent affliction. When you are colorblind, it is as if the color option is forced off, and any items with colorful random appearances cannot be distinguished from one another (all gems are just "a gem", all colored potions (but not ones such as fizzy, bubbly, white, black) are just "a potion", ditto for colorful spellbooks) until formally IDed. Figuring out how calling object classes works might be tricky, because having it work as it currently does would mostly nullify the identification challenges of being colorblind.

aosdict, jonadab

A new "illusion" monster spell, which makes the caster or an allied monster appear as another monster until something disrupts the illusion (you attack it, it attacks you, it takes damage from some other source). Monsters specifically cast it when you cannot see the target monster. The illusion favors nasty monsters, but low-level spellcasters may only be able to create illusions of somewhat higher level monsters. A potentially evil addendum is that high-level spellcasters may use the spell to make themselves or other powerful monsters appear to be weaker monsters.

aosdict, jonadab

Rays should reflect erratically or not at all from non-wall rock terrain, Walls are smooth, but rock is rough.

aosdict, FIQ, jonadab, ais523

Fire and cold should both work as a cone, and should spread out over distance and possibly hit multiple targets, but with damage decreasing over distance.

jonadab, FIQ, hothraxxa

When trying to descend stairs while stunned, and possibly confused with some probability, you fall down the stairs.

AmyBSOD

A Word of Recall spell, which after a sizeable delay (3d5 or 5d6 turns) levelports you to one of several possible locations: Minetown, dungeon level 1, the Oracle, the Castle, the Quest. You will not travel anywhere you have not already visited. Does not work if you have the Amulet.

ais523, jonadab, FIQ

King monsters should spawn with an entourage of monsters; e.g. a gnome king should create several other gnomes around him upon generation, with preference given to gnome lords and possibly gnomish wizards. If monster pets are implemented, they should behave as the king's pets, and the king may generate with a magic whistle.

FIQ

The ring of protection from shape changers should apply to the wearer as well as other monsters; if the wearer has lycanthropy, they will not transform; if the wearer is a different shapechanger like a vampire, they cannot transform.

aosdict, FIQ

All characters should start with a minimum of 11 HP, so they don't get one-shot by a falling rock trap on turn 1.

FIQ

More monsters should be locked to the grid and can only move orthogonally, like grid bugs.

ais523, jonadab

Have a record in the xlogfile of whether the game was likely a startscum, for analysis purposes. It's easier for the game to track things like fountain quaffing and using obvious dangerous items. How exactly this would happen is not determined; the game probably shouldn't try to make a decision itself, there will be some false negatives and positives, but storing fields for everything like "number of times quaffed from a fountain" is probably bad too.

ais523

Nonwishable unique items or artifacts that would be "nice finds" in the dungeon.

FIQ

Race and polyform should not be distinct; they should be merged into a single permonst or corpsenm-like variable. Role is independent of race, and perhaps every monster should be described with a monster/role pair, with the role being null for most monsters (i.e. gnomish wizards are just gnomes that are also wizards). This might eliminate the entire concept of player race, internally, but transferring some of the racial effects on players (e.g. elves' sleep resistance at XL 4) might be tricky.

ais523, FIQ

Change zombies' and possibly mummies' claw attack to a bite attack.

jonadab, aosdict

Split curse resistance off from magic resistance. Curse resistance is granted only as an extrinsic by a couple of artifacts, including Magicbane, and maybe some mundane item that isn't any good otherwise (a mummy wrapping?), and behaves like Magicbane's curse resistance does currently ("You feel a black aura surround the <item>.") Half spell damage without curse resistance no longer helps limit the number of cursed items, and a curse may still manage to bypass resistance, with current probabilities. There could also be an amulet versus curses.

jonadab, aosdict, NeroOneTrueKing, PavelB

Make Quest nemeses death-magic resistant.

ChrisE

Ideas around a system in which you can cook corpses:
The general idea is to unbreak the hunger system by making regular corpses unsafe to eat, so the shortage in resources isn't in food itself but is in safe methods of cooking it.
Cooking sets a corpse's rot timer to 0, lets them go longer without spoiling, or unspoils them.
May also remove poison from some kinds of poisonous corpses.
Cooked corpses are unsuitable for sacrifice and less likely to give intrinsics, or don't at all (because the vitamins are destroyed).
Can apply wands of fire to cook corpses.
Or maybe eating raw non-vegetarian corpses is just plain dangerous, causing vomiting or sickness or other bad effects.
Corpses can be cooked by killing monsters with fire or hitting monsters with fire attacks while they are carrying corpses.
The problem is that nobody has yet proposed a mechanism for cooking corpses that would work well. Having firewood or some similar thing would massively affect the early game between characters that can and cannot manage to find it, and roles that start with or without it. Wands of fire have been proposed as a resource but those are valuable. Introducing a new item like firewood means that a whole lot of mechanics have to be reviewed for whether they should interact with or create that item.

Agafnd, ais523, aosdict, Grasshopper, Chris_ANG, thelemur, FIQ, AmyBSOD

Implement "spoiler novels", cheap books like 3.6 novels that contain spoilers. (Not described in what form the spoilers would be. Several true rumors?)

FIQ

Lycanthropy fixes:
It triggers much more rarely, every couple thousand turns, but while you are in your beast form you lose all control.
Or it triggers much more predictably, with messages making it clear that a change is coming, and the duration of the change is both more limited and more predictable.
Or it triggers on a certain damage threshold or after taking a particularly strong hit, determined by your level, HP max, and phase of the moon.

FIQ, ais523

Invisibility works completely when the invisible monster and the detecting monster are far away. When within 5 (or 4?) squares of each other, its location is known to within 1 space (fuzzing the real location by 1 space in all directions). When the invisible monster takes a direct offensive action, or with some probability when it is adjacent, its position becomes known. It still appears as I, but the I will move wherever the monster goes until it becomes 5 or more spaces away, at which point invisibility once again works fully. This could work differently if the invisible monster is stealthy.

FIQ, ais523, aosdict

Change the message for gaining intrinsic shock resistance to be "Your current health feels amplified!"

FIQ

Since boulders are round (clearly so; any character regardless of low Strength can roll it easily), and corridors are presumably not round, you can always squeeze yourself into the opening between the boulder and the corner of the passage. Inventory weight does not matter, because any reasonable character would push their knapsack through the opening first, rather than trying to go through while carrying it.

aosdict, jonadab

You can #invoke the Amulet of Yendor exactly once for a wish, with some unspecified major drawbacks.

FIQ, jonadab

Finger of death is renamed to touch of death, and works equivalently to the monster spell (melee range only, and it may fail). Because of this, its level should be reduced, which for some people means that there should be a replacement level 7 attack spell (ball/ring spells might work here).

aosdict, FIQ

Shop generation chance increases for every level with no shop, and decreases/is reset when one is generated.

bug_sniper

In UnNetHack and other variants with a black market, you never hear "You hear someone cursing shoplifters" in the black market, unless you have angered One-Eyed Sam.

UnNetHack

aosdict

Remove the bell from the list of musical instruments that Elf characters can receive at the start of the game. This is because it's atonal and its only half decent use is to attract pets (note that elves can't get tin whistles, so clearly summoning pets is not important enough to qualify something for initial inventory).

aosdict, ais523

Soldiers occasionally drop piccolos, which act similarly to wooden flutes (maybe they're made of metal though).

bug_sniper

New artifact Aegis: is a bronze roundshield (which is supposed to have Medusa's or another gorgon's face impressed on the front). Can be invoked sideways at a monster, which petrifies it or, failing that, causes it to flee (regardless of difficulty or monster MR). Can be invoked downwards to burn a Gorgoneion in the floor. Possibly grants stoning resistance or gaze resistance while equipped.

dNetHack

NeroOneTrueKing, rikersan

Thrones will not disappear in a puff of logic unless at least one interesting effect from sitting on them has happened.

ais523

Saddlebags, a rarely generated container that can be applied to a saddled mount and then have gear put into it, allowing the player to offload some of their weight onto the mount. While they are as nonmagical as a sack, they have a higher base cost and weight. You can loot it on an adjacent mount by using the directional #loot command. Knights may start with one.

aosdict, yuring

Make all magic portals on the Elemental Planes immediately visible. The challenge should be surviving for long enough to get to the portal, not wandering around till you find it. This is because "Hunt for the Magic Tile" already exists on the vibrating square level, and is not very compelling.

jonadab

Implement a strangulation or "can't breathe" timer, which unifies strangulation, suffocation, food choking, rope golem choking, and drowning, and also provides a clean way for monsters to have a suffocation attack.
This means that choking over food is no longer instantaneous. Each turn while choking over food, you have a 20% chance to vomit and lose 1000 nutrition. At certain points while the strangulation timer is getting closer to 0, you take one point of Con damage.
Drowning monsters now grab and pull you underwater in 1 turn, but you have until the timer runs out to kill the monster or escape in some other way. Lifesaving while drowning does not give you a free escape, but resets the drowning timer.
Rope golems are now more dangerous, since they represent a delayed instadeath.

jonadab, aosdict, FIQ

Ankh-Morpork levels in the Tourist quest should be populated with some peaceful humans, dwarves and trolls. However, the levels should also then avoid having lots of narrow corridors so it's not incredibly frustrating to traverse them.

aosdict, jonadab

You take fire damage from standing next to lava, levitating or flying over it, or walking on it. Damage from standing next to it is (number of adjacent tiles)d8, whereas being over or on lava has rather higher damage. Fire resistance does not prevent this damage completely.

aosdict, FIQ

If you eat the corpse of something and a monster of that same class sees you, it becomes angry. (This is from ADOM).

FIQ

Luck factors into enchantment wishing.

rikersan

For Luck balance, there should be some Luck-based effects that are really good at low Luck but get kind of meh at high Luck.

aosdict, rikersan

Poison is either changed or extended so that it is a lasting status condition that gives you negative HP regeneration, or some other source of this property is added.

jonadab, AmyBSOD

Skeletons, or any monster with the MS_BONES sound, rattle their bones periodically, which frighten the player into helplessness for a few turns.

AmyBSOD

Potion equivalent of extra healing for magic power, or else some consumable way to recover 20-40 power in one go; the normal potion of gain energy is currently more useful for raising maximum power than it is for restoring it. This new thing need not be more effective than gain energy is at raising maximum energy. (Perhaps "potion of restore energy", which does not raise maximum at all.)

aosdict, ais523

Attempt to address the ascension kit problem: make the highest-tier, really good quality, +8 or +9 gear be generated on the toughest monsters or even bosses deep in Gehennom. The high enchantment makes it incredibly hard to get through normal means, even if the base gear is wished for elsewhere. Overall difficulty would need a bump if the average player is expected to pick up and use some of this gear.

aosdict, rikersan

Non-inaccessible closets have a small chance to contain a monster on level generation.

jonadab

Pets eat at a consistent rate that does not depend on their speed, so the number of turns to eat something depends only on corpse size. Pets should also stop eating when hostile monsters approach.

Grasshopper

Reduce the cost of a major Oracle consultation; the current price could be too high for unspoiled players to consider it worth it.

ais523, aosdict

A Barbarian rage mechanic (possibly an effect on Cleaver replacing its current damage bonus) where a damage bonus is assessed based on how long ago you last killed a monster. Originally a buff to Vorpal Blade where it beheads anything it hits if the last behead was N turns ago, but this is unbalanced.

ais523, aosdict

Elaborations on the Fort Ludios minesweeper proposal by ais523:
Should spaces with 0 neighboring mines get 0 gold? Good because it makes the game possibly more instantly recognizable as minesweeper, bad because it makes the overall amount of gold less predictable
Need to guarantee somehow that the person stepping into the room doesn't trigger a mine instantly, and set up the level accordingly.
The column nearest the entry door could be clear of mines and gold.
The whole border could be clear of mines. However, this means that the total amount of gold must end up being an even number - not ideal.
What happens if a monster steps on a mine?
Possibly this needs an Oracle consultation to explain it to unspoiled players. Or make an engraving when you enter - possibly "xyzzy" as a reference to the cheat code in Windows Minesweeper. Or start off with one mine uncovered and identified on sight.
The number of adjacent mines could be expressed in the ones digit of the gold amount. Possibly with a large round number added, so every space is 3001 or 2002, which hopefully clues the player into the fact that it's a significant number. But this might be too restrictive.
How to reach the magic number 69105, and do so in a way that guarantees it can be generated? May need to bias the level generator so that this must happen.

ais523, aosdict, jonadab, FIQ

Land mines should blast the player away in a random direction, not make them not move and fall into a pit.

FIQ

Add some region code preventing monsters from generating in (or even better, moving into) the pit corridors in Sokoban until the level is solved.

jonadab

Replace Venus with Diana and Mercury with Apollo in the Ranger pantheon. This is nice because Apollo and Diana are actual gods of archery, and it removes the Mercury/Hermes conflict with the Healer pantheon.

aosdict, Mandevil

Liches drop or are generated with fairly good magical items, like potions, scrolls, spellbooks and even wands, to incentivize not genociding them.

aosdict, NeroOneTrueKing, rikersan

Mummy traps, a new trap type that generates with a very desirable item: highly enchanted gear, magic markers, items with object properties, etc. However, when you pick it up or interact with it in any way like teleporting it or having a pet collect it, a bunch of mummies appear around you (they would obviously need to be more threatening than they are right now). Also can have a "mummy room", a special room that contains one mummy trap and nothing else.

FIQ, jonadab

Candle additions:
Wielding a candle gives it a light radius of 3 (at the obvious expense of not having a weapon).
Hitting enemies with a lit candle (thrown or melee) has an 80% chance to extinguish the flame and a 20% chance to light them on fire, doing 2d3 fire damage.
A lit candle can be applied to an adjacent burnable object (door, tree, wood golem, paper golem) to light it on fire.

aosdict, Khor, FIQ

Djinni (except on the Plane of Air) may drop a scroll or wand of wishing when killed. But when you kill a djinni, all future djinni will spawn hostile.

bug_sniper, jonadab

Add rare drops to some monsters, with a very low probability (around 0.1%). These could be artifacts or otherwise unattainable items.

Khor

There should be one major monster of each alignment that is ungenocideable: Archon for lawful, deep ettin for neutral, arch-lich for chaotic.

FIQ

Allow taming of player monsters in bones with one prerequisite: you must tame its ghost, draw the ghost over the corpse, and then revive the corpse. To facilitate this, killing a player monster should always generate a ghost over the corpse, possibly with a gravestone and 80% of inventory being cursed.

aosdict, FIQ

Services center: a shop containing shopkeepers who offer services but have no goods to sell.

SLASH'EM

bug_sniper

If crafting were added to the game, saddles should be one of the craftable items.

AmyBSOD

Mind flayers cannot tentacle you if they are cancelled.

FIQ

Foocubi levelport instead of teleport.

jonadab

If you ascend with your alignment mismatching your align0 (meaning you changed alignment at some point), the death is extended to "ascended in dishonor".

Neko-chan, FIQ, aosdict

Make candle stacking for more light actually useful and realistic: the number of candles required for another square of radius increases quadratically instead of exponentially, so 1 candle gives radius 2, 4 give radius 3, 9 give radius 4, 16 give radius 5, etc. Later extended into a more general idea allowing light sources of any type to stack: candles each give 5 lumens (because a single candle's light reaches up to sqrt(5) squares from the center), lamps give 10 lumens, potions of oil 2, and the full Candelabrum gives 20. To compute your total light radius, add up all the lumens and take the square root.

ais523, aosdict

Several improvements to the level-defining des files:
General goal is to be able to get the MAP as close to pasteable into the wiki as possible.
Interpret &lt; and &gt; on the MAP as STAIR commands for that specific spot.
Interpret&nbsp;? on the MAP as "terrain to be filled by this level's filler algorithm". (This would allow for things like Asmodeus' Lair to not have to be chunked into multiple pieces).
Allow ^ to be placed on the MAP, and it is an error if there is no TRAP command for that space (the parser will assume that ordinary floor should be the type of floor). Same for + and DOOR, and for boulders.
Allow monsters' inventory to be specified.
Allow objects to be specified by random appearance, with a flag that defines whether it will pick a random item or simply fail to generate if that random appearance does not exist in the game.
Allow the level size to be specified so that ROWNO and COLNO are out of the question.
Extend 3.6.0's REPLACE_TERRAIN to work with non-rectangular areas.
Most importantly, parse the files with something not written in yacc, because this adds an additional layer of complexity to anyone who wants to work with the code.
Maybe even read in the .des files at runtime, so they can be modified without doing a recompile of them and the intermediate .lev form isn't even needed. This would require giving each level its own .des file and distributing them with the game. This means you don't get the benefits of using a parsing library, but you no longer have to code for or depend on that library either.

aosdict, rikersan, jonadab

Change the Knight quest artifact to be the Holy Grail. When quaffed from, something good happens; perhaps it needs to have charges or #invoking it fills it up so you can drink from it (and you don't have to drink from it immediately, allowing strategic choices). Should give magic resistance when carried. Possibly gives the effect of a random potion when quaffed: always a "good" potion when blessed, a random one if uncursed, and a "bad" potion if cursed. Or it blesses items dipped into it.

aosdict, Anag, Neko-chan

Make the Magic Mirror of Merlin give slotless reflection instead of magic resistance; this is more thematic and makes for more interesting strategy.

Neko-chan, stenno, aosdict, Anag, rikersan

Rebalance armor so that all "mail" armor and most of the iron body armor in general is not useless. Ideally, the worst iron armor (orcish chain mail) should be considerably better than studded leather, but they are equivalent. The ideal balance, keeping leather armors and all weights constant and not accounting for to-hit or damage reduction, is probably something like the mails going up to 9 or 10 AC, and splint and plate getting up to around 14, but this is not possible to implement without changing the combat system.

aosdict, stenno, Anag

If you try to eat an artifact and it blasts you to death, put YAFM in the death message: "killed by trying to eat the [artifact]".

Wooble

Cancelling shades should remove their incorporeal ability to not be hit by anything, and they should then be hittable normally.

HTTPS

Monsters that are in a "wait for the player" state should use different AI for decision-making (i.e. not using their teleport control to attack the player).

FIQhack

jonadab

Pool rooms, a special room type that consists of a perimeter of normal floor surrounding a region of water taking up the rest of the middle of the floor. It is populated with sea monsters and some sunken treasure. It could also contain a fake bones pile, a pun on "bones pool".

Unknown originator, aosdict

Elves should be able to squeeze between two trees diagonally.

jonadab

Knights start mounted, or else are trained enough to mount their horse from turn 1.

ais523, FIQ, jonadab

Level teleport in the Quest never goes down unless you have beaten the nemesis and never goes up unless you have shown the artifact to your quest leader.

AmyBSOD

Wearing a cloak of displacement allows you to displace pets 100% of the time and also peacefuls; this still works if you are confused, stunned or hallucinating.

AmyBSOD

Player monsters, crossaligned priests, and hostile angels on the Astral Plane are able to steal the Amulet from you. Should they get it, they will try to make a beeline to their high altar to sacrifice it. The player is also able to steal the Amulet back, though; and wearing the Amulet acts as one turn of protection against it being stolen; an attempt to steal it will just remove it from your neck. If something else ascends, your game ends in an escape. However, all these monsters are hostile towards the Amulet-bearer, not you; so if it gets stolen from you, the pressure will let up a bit.

aosdict, jonadab, FIQ

Invisible monsters wearing a mummy wrapping show up as an I (you don't get to see what they actually are), but an I that moves and doesn't persist on the map.

aosdict, jonadab

Gentle relaxations for the quest XL requirement:
It is waived if you have set the "descent into Gehennom" flag by going downstairs from the Valley.
It checks maximum XL reached, not current; so if you have ever been XL14 it doesn't matter if you have been drained since.
It is waived if you have the demigod flag set from killing the Wizard of Yendor.

aosdict, AmyBSOD

Sickness resistance negates the effects of potions of sickness. However, a cursed potion of sickness will now give you fatal illness instead of the normal poison effects.

bug_sniper, aosdict

Your god respects any conducts you currently have when giving you stuff. If illiterate, will not give you a spellbook. If weaponless, will not give you artifact weapons (maybe could give a +1 intrinsic damage bonus instead). If pacifist, may send tame minions. However, this is only if your deity is lawful or neutral - chaotic gods will ignore these rules and give you whatever.

FIQ, aosdict

If the hero has see invisible while ascending, swap the line "An invisible choir sings, and you are bathed in radiance..." out for some other YAFM. Perhaps even something as subtle as "A visible choir".

LichenSink

Blessed potions of polymorph, when quaffed, grant you immediate polymorph control over just that one polymorph either 50% or 100% of the time. To compensate, cursed potions of polymorph will ignore changing into a dragon and will try several times to roll a monster that will make you break out of your armor. Or the cursed potion could have a wildly variable duration, so you have no idea when it will end and cannot rely on it.

rikersan, aosdict, ais523

Attempts to analyze good instadeaths versus bad instadeaths (loosely defined as ones that are instant hard-to-avoid deaths that aren't really similar to running out of HP):
Poison, digestion, lava, death magic, and drawbridge instadeaths can easily be converted into HP damage of max(damage dice roll, substantial&nbsp;% of your max HP).
Drowning and choking would be well-suited to a breath system, where it becomes a delayed instadeath. Especially so if you can stop the clock by putting on an amulet of magical breathing or praying.
Intelligence drain and level drain generally can't happen without the player being given ample time to escape, so they are fine.
Starvation could be changed to HP loss, but you usually just die from side effects of fainting anyway.
Instadeaths that almost always have to be intentionally caused by the player (self-genocide, divine wrath etc) are generally fine as-is.
Instakilling artifacts are problematic, because there is currently no recourse except for the amulet of life saving.
Eating or digesting the Riders should not instakill without warning, because it is now unexpectedly a bad idea to eat a reviving corpse, whereas it had been a good idea in the rest of the game.
Good instadeaths generally use unusual resources to fix, or hit the player's reserves in an unexpected way, and allow the player a chance to get out or stop it before dying.

NeroOneTrueKing, aosdict

Chemistry golem, which spawns with some potions that it will either throw at you or quaff.

AmyBSOD

You can go to the Astral Plane early, and by waiting around there long enough, eventually a player monster will spawn with the real Amulet, at which point you must prevent them from ascending and claim the Amulet yourself.

AmyBSOD

In variants or proposals where you can kill your quest leader to get the Bell of Opening, if you have permanently converted alignment already, killing your Quest leader does not give you a massive alignment penalty.

aosdict, ais523

Decide once and for all whether alignment record should be god-specific or god-agnostic, because NetHack currently tries to do both and fails. Things like the massive penalty for killing a Quest leader make way more sense for lawfuls than chaotics.

ais523

If the Wizard of Yendor's monster ID is a multiple of 1000, he should be named the "Warden of Yendor".

FIQ

Gods are more likely to give gifts for higher-difficulty sacrifices.

aosdict, Wooble

Rename the amulet of restful sleep to the amulet of narcolepsy.

thelemur

Lawful and neutral gods are angered (or do something angry) if you consort with a foocubus on their altars or in their temples.

Porkman

Make permaconverting harder to do by accident, since confusing the actions of rededicating an altar and rededicating yourself seems unlikely. Maybe make it happen if you sacrifice or pray on a crossaligned altar while confused.

ais523, aosdict, thelemur

Zapping a corpse with a wand of cold will increase its decomposition timer (making it take longer to rot). If already rotten, only scales it back to rotting age.

thelemur

If attribute changes from exercise and abuse are blocked due to the ring of sustain ability, they accumulate, and once you take the ring off they will all gradually apply over the next few exercise cycles.

aosdict, jonadab

Add in master lichens as a real monster, which are only a bit more threatening than normal lichens (maybe speed 2 or 3, have a passive sticky attack like mimics) but have an increased difficulty so that they generate deeper in the Dungeons, and are a source of nonrotting corpses. Possibly, the passive sticky attack should also be given to regular lichens.

aosdict, greeter

Add a scroll of air (as well as the scroll of flood, which is renamed to the scroll of water) so that there is one scroll for each element. When read normally, it could give a message "You feel a fresh breeze" and either reset your strangulation counter or give you temporary breathlessness. (Breathlessness seems like a potion effect more than a scroll effect, but then again, during those times when you need emergency breathlessness, you're probably not capable of quaffing a potion.)  If you read any of the water, earth, fire, and air scrolls while confused, it summons elementals, whose tame/peaceful/hostile state depends on the beatitude of the scroll.
If you read it while on the Plane of Water, it either creates a new air bubble if you're not in one, or expands your bubble permanently if you are in one. If cursed and in a bubble, the bubble shrinks to one space.
SpliceHack has since implemented the scroll of air as an burst of wind that shoves adjacent monsters away in all directions.

FIQ, bhaak, AmyBSOD, aosdict

Erosion has more than four states, though it still only displays as "eroded", "very eroded", or "thoroughly eroded"; different rusting sources can cause different levels of rust (e.g. dipping a long sword in a fountain or getting hit by a rust trap would probably only cause a small amount of rust, whereas a rust monster might cause a lot.) This would enable a more fair way to have things "erode away completely" like they do in Grunthack, since you would be able to disengage any thoroughly eroded piece of gear before it was at serious risk of vanishing.

jonadab, NeroOneTrueKing, aosdict

Cut all map sizes in des files down to at most 20 lines tall, so that there is extra space for messages and status line in an 80x24 terminal. Few levels currently use all 21 lines.

FIQ, ais523

Give the player a slightly different warning if they attempt to go up on the DL1 upstairs after handling the Amulet, if they do not have the real one.

NeroOneTrueKing, aosdict

Gods' "Prove thyself worthy or perish" message is flavored as "Prove thyself worthy, because I can do no more for you". On the Planes, the gods' balance of power prevents your deity from granting you any extra help (apart from sending angels when you arrive in Astral). If this were not the case, one would expect to be able to breeze through the Planes, with your god smiting down any enemy that might threaten you getting them their Amulet. Prayer will not work, though it will still break atheist conduct.

aosdict, NeroOneTrueKing, Tarmunora

A priest-friendly artifact that is a potion or tool that acts as a "holy water well" - maybe it slowly but infinitely fills up with holy water, up until it is full?

Porkman

Shattering a lit potion of oil on the ground will create the normal fireball blast on that spot.

FIQ

Every hit with a wielded weapon, up to 20, decreases the chance of being given a non-weapon artifact.

dNetHack

rikersan

Farlook allows you to see a list of all items on a square as if each were the only item on that square. Items hidden under others are not obscured. Also works if there is a monster standing on the square; you can still see the items under it.

raisse, ais523, aosdict

Bed, a \ which if you #sit on it makes you fall asleep for d10 turns or you have fully recovered your health. While sleeping on the bed, you get hungerless regeneration. Found in barracks and some special levels. Breakfast not provided.

aosdict, Grasshopper

Store type "sushi restaurant", which sells&nbsp;; corpses, kelp fronds, various sushi rolls, and sushi mats, tools which allow you to combine kelp and&nbsp;; corpses into higher-nutrition sushi rolls. Sushi rolls include kraken sushi, eel wrap, and shark tempura.

bug_sniper, aosdict, Grasshopper

You can #force boulders where there is a monster behind the boulder to displace it, or crush it if it is in/on a pit or a hole. Based on Strength, only works if monster is medium or smaller.  Always displaces unsolid monsters, of course.

bug_sniper

A lamp with the same unidentified appearance and base cost as a magic lamp. It is a charged magical tool (has a lifetime, comparable to an oil lamp) that sheds no light, but instead detects unseen in its range whenever it is turned on. This includes invisible monsters, secret doors, and all traps. It also allows vision to penetrare through clouds.

rikersan, raisse, aosdict

Change the sickness instadeath to a HP-based form of damage, since it is very obscure about how long you have left to live and can be drastically reduced.
Instead of a death timer, apply a penalty to HP regeneration rate, with this penalty being variable and slowly decreasing as you recover from the sickness. This is nice because it allows for monsters to have a sickness attack in the early game.
This penalty can be large enough to make your regeneration rate negative.
Getting hit by a sickness attack while already Ill not only increases the severity/duration of your illness, it deals some extra damage proportional to the severity of the sickness.
Severe enough sickness only partially times out - you will need to take some actual self-healing action like quaffing healing potions, praying, casting cure sickness, applying a unicorn horn, etc. to be completely cured.
Unicorn horns no longer cure the entire illness all at once - they will only reduce the severity (which might cure the illness all at once if it's mild).
Being sick for a long time may cause vomiting, Con loss, Str loss, and occasionally hallucinations.
Sickness will eventually go away on its own if it's not bad. Maybe look to FIQHack zombification disease for specific mechanics for how this could work.

NeroOneTrueKing, aosdict, Tarmunora

Unicorn horns no longer cure afflictions completely; they will only reduce the duration of one.

NeroOneTrueKing

When rock-eating is implemented (or in variants that already have it), eating a luckstone gives you -1, +1, or +2 Luck depending on the beatitude of the stone.

aosdict, bug_sniper

#sitting on a trap will trigger the trap while ignoring any magic resistance you have, so that you don't have to disrobe.

rikersan

The Master of Thieves has a stealing attack that allows him to choose intelligently what to steal.

FIQ

Expert-cast levitation, or a blessed potion of levitation, grants flight instead of levitation.

Tarmunora

The game should ask to confirm when you try to throw something that is not intended to be thrown (for example, if you unwielded your bow and are now trying to throw arrows).

FIQ

You can teleport dungeon features (except high altars, of course.)

rikersan

When you ascend, you receive an elaborate role-specific message with your quest leader congratulating you (if they are alive).

AmyBSOD

Polymorph traps do not instantaneously polymorph you; instead they start a short timer during which the player has time to either stop the polymorph from occurring (through healing potions, or prayer, or some other decently common consumable) or put on a ring of polymorph control or amulet of unchanging. However, magic resistance no longer protects against this effect.

jonadab, aosdict, FIQ

Add more non-magical ways to get pets that are better than what your starting pets can level into. Such as pet stores with figurines, or being able to tame watchmen by paying them money, or by healing a monster at low HP.

FIQ, aosdict

Attempting to move healers out of the petmastering role: they now have skilled medical knowledge that enables them to hit monsters in melee with a scalpel or knife to inflict a "bleeding" status effect which will cause the monster to lose HP continuously. Any role is able to do this with a scalpel, but the effect is much more limited than it is for Healers. This means that for a Healer, combat now consists of hitting a monster to make it bleed, then disengaging and keeping away from it in the hope that it dies on its own. The Staff of Aesculapius no longer drains, instead it heals the damage it would have dealt (unless the Cyclops has it, in which case it drains life like normal.)
Additionally, the Staff of Aesculapius no longer has level-draining powers. Instead it has a drain HP attack that heals the wielder.

aosdict, FIQ

Add herblore (possibly as a non-combat skill). This allows you to brew various potions using herbs and potions of water. Healers are quite good at it, and their quest contains many herbs. Requires actually implementing herbs, which cannot be planted or grown like in ADOM.

aosdict, FIQ

If two-way level communication is implemented (meaning that trapdoors and such deterministically go to a specific space on a specific lower level), allow the player to go back up through holes in the ceiling with levitation or flying, or allow them to place ladders there that become a &lt; to do the same thing.

bug_sniper

Yellow lights possibly have a light radius of larger than 1. Also add white lights, y, which are very bright, have a radius of 3 or 4, with a blinding gaze attack and no explosion attack (unless keeping the explosion attack is too thematic to the y class, in which case it should blind for a long time).

jonadab, aosdict

The player is given the ability to seduce peaceful characters in a fairly weak, non-magical way (to get better shopkeeper prices and such). This is initiated if you #chat to them while wearing no armor. Works best when the target is the same race as you, you are opposite genders, and you have high Charisma. Possibly, seducing a priest in a temple risks the god smiting you.

Tokage, aosdict

Chameleons only transform into monsters close to them.

Tokage

Uncontrolled teleportitis counts as a minor trouble; a god may decide to fix it by removing it, but only if there are no other troubles. If there are other troubles, teleportitis will not be removed.

Tokage, aosdict

You can wish for magic items that have a "bane" versus one specific monster type. The weapon deals massive damage to that monster type but has no other advantages.

Tokage

Remove deathdrops entirely, and instead give monsters items in their starting inventory with the same rules as a deathdrop.

jonadab

Vary the monster AI for using miscellaneous items; some monsters like trolls are "hoarders" and will not use misc items unless there is a compelling reason to do so; others will use them at the first opportunity.

jonadab

If a player crafting system existed, tallow candles should be relatively easy to make (because they can be made out of slain animal fat).

aosdict, AmyBSOD

A flying monster with a displacement attack, which attacks from water in order to displace you into water. Also a bull monster that charges at you, and will either displace you if you pass a Dex save or gore you.

jonadab, aosdict

Elbereth should not work until the hero discovers it in-game. (Similar to dNetHack's wards.)

K2

Elbereth should work from the very outset of the game, but get less effective over time.

jonadab

Bias the probability of bones files to be a general bell curve fixed on around level 10-15.

rikersan

Expert and higher martial arts lets you hit twice, but only if your first attack hits and you are wearing no shield.

jonadab

War hammers are a two-handed weapon, with much higher damage than they currently have. Slashing and (maybe) piercing weapons no longer get a Str bonus to damage, only bludgeoning ones do. Probably need to rebalance weapon damage types and attribute bonuses completely.

jonadab, aosdict, FIQ

When #turn destroys undead outright, it prevents them from leaving a corpse.

Tokage

The Archeologist quest has either a lot of fairly weak artifacts or a lot of mundane items (golden staffs, death masks, sacrificial daggers etc) that are worth a lot of money in the locate and goal levels of their quest.

aosdict, rikersan

If Orcish Town is generated, guarantee a "peaceful" Mines' End where all the inhabitants, surviving shopkeepers, watchmen and the priest have fled. Chatting to the priest will make him ask you to clear the orcs out of Orcish Town, upon which chatting to him again will make him grant you a protection boon and give you a luckstone.
This can be done by setting a global flag if and only if Orcish Town generates, and only load the peaceful Mines' End if that flag has been set. If you manage to get to the bottom of the Mines without yet generating Minetown, you are guaranteed not to generate the peaceful Mines' End, and Orcish Town will not generate either.

FIQ

Alignment record changes: chaotics get -1 penalties over time for failing to do any chaotic behavior, neutrals get +1 alignment bonuses more slowly over time by not doing anything, and lawfuls get neither of these and need to get their bonuses on their own. Alternatively, lawfuls accumulate bonuses by doing nothing (not breaking the law).

ais523, FIQ, aosdict

The Heart of Ahriman grants half physical damage, and Thoth Amon is nearly guaranteed to pick it up.

rikersan

Weapons can rarely randomly generate as erodeproof.

rikersan

The Orb of Detection grants searching in a region of radius 2.

rikersan

The Norn and Valkyrie quest friendlies have different messages if you talk to them after having been changed into a man.

Jendic

Lizard scales, available as a drop from killing a lizard, are wearable as AC 1 body armor. They can be upgraded into lizard scale mail, which has AC 3. This armor protects you from petrification.

Porkman

Add a field to struct rm (or possibly reuse the flags field which is 5 bits) that determines the type of tree that is on that space, if typ == TREE. This enables you to control what kind of tree it is, and what kind of fruits you will get by kicking it, and whether you can get bees from it. Also add a level flag that allows a level designer to specify that all trees on the level should be barren.

jonadab, aosdict

Include a kitchen sink in plans that add a separate reward level above the top level of Sokoban, or in that level (so that anyone wearing a cursed ring of levitation there has some recourse to get back down).

ais523

"Omnicidal" monster attribute: it attacks peaceful, hostile, tame, and possibly other omnicidal monsters. Suggested in relation to monsters reading cursed genocide or creating monsters.

ais523

Female oviparous monsters sometimes drop eggs of their species when killed. The chance is reduced if the monster was dead and revived.

FIQ, jonadab, aosdict

Add "There's no replacement for displacement" to the list of random engravings.

rorre

Make the "Destroy old game? [yn]" prompt harder to destroy a game than simply hitting y. Probably ask "Are you sure?" and force the user to type out yes.

aosdict, jonadab

Knights instakill by checkmating all "king" monsters that are a knight's-move away and are surrounded or cannot move.

geoffspear

Knights pass over monsters in their way when doing a knight's-move jump.

FIQ

Samurai have an ability (maybe a special ability) to displace hostiles.

FIQ

Tame dogs and cats should not grudge each other.

FIQhack

aosdict

Jousting should be affected by riding skill.

FIQ

Ring and amulet hunger should be counted all on turns that are a multiple of 20, to close the two-slow-digestion-rings loophole.

aosdict, greqrg

The ring of slow digestion has no ring hunger, but instead prolongs hungering by a factor of 20 (presumably hunger decreases only on multiples of 20 turns). Wearing 2 of them prolongs it by a factor of 400.

FIQ

When killed by a monster that brings you back as something else (zombie, vampire, green slime), you might not die; you may continue playing in that form with permanent intrinsic unchanging. This might make it actually beneficial to get killed by a vampire, so the chance of continuing can't be 100%, or else it can only work in a limited set of mostly-uncontrollable circumstances (like maybe a vampire's or zombie's bite takes you down to exactly -1 health). Green slime death is probably okay to stay at a 100% chance, though. Also needs some thought for how the unchanging squares with being a vampire and wanting to #monster into different forms. Perhaps intrinsic unchanging, unlike extrinsic, allows a monster to change into its normal alternate forms, but nothing else. Some other downsides should possibly be present too, like you don't get your normal amount of HP and are stuck with the amount given by your new form.

aosdict, jonadab

If someone throws a potion of sleeping at you and you die while asleep, the death should not say "while sleeping off a magical draught".

raisse

A t class monster that generates on a wall space and pretends to be part of the wall, then attacks/eats you when you step next to it.

jonadab

Artifact YANI: the Phial of Galadriel. It is a potion of starlight that has some neat carry effects and drink effects.

dNetHack

aosdict

In variants that give Geryon a lair, implement his two-headed dog Orthus.

aosdict

Tame monsters continue to hold grudges against each other, unless the master's Charisma is high enough.

FIQhack

NeroOneTrueKing

If wind dragons are added, their scales should grant speed or slow resistance in addition to flight.

FIQhack

aosdict

Reduce gnomes' Str and Con caps, but ensure they get decent Dex and Int. They should be obviously different to play than humans (rather than being mostly superior). Dwarves should have a Wis cap of 16. Elves' Dex cap should be higher than humans'.

jonadab

Expert lightning doesn't create a lightning explosion on the first target it hits; it creates chain lightning instead that may hit adjacent targets.

FIQhack

jonadab

Add a few more sources of the uncursed charging effect, because charging resources are rare enough as so that things like common wands never get recharged by players.

AmyBSOD

Give YAFM when a monster uses a bullwhip on you while you are polymorphed into a foocubus.

AmyBSOD

Ovens, a dungeon feature (\?) that you can use to cook food, light items on fire, and test potions in a safe, controlled manner like you can with rings and sinks. This happens by putting the potion in the oven and it produces some cosmetic message that can be used to identify it.

statuesurfer

Jetpacks, a chargeable source of levitation/flying. They are worn in the cloak (or body armor?) slot and grant 0 AC.

statuesurfer

The scroll of remove curse's blessed effect is transferred to its uncursed effect. The blessed effect is now to uncurse everything in inventory, and then bless a few items. The cursed effect now randomly curses inventory as the curse items spell would do. May need to make this scroll rarer or more expensive to write in order to keep it balanced.

statuesurfer

The Master Assassin has an instakill attack (though not unpreventable; the player should be able to prepare and protect themselves some way).

FIQ

Add a scroll of polymorph. Blessed polymorphs you with polymorph control over this one occasion; uncursed polymorphs normally; cursed polymorphs you and everything adjacent to you.

statuesurfer

If you're hallucinating and get the "You can't handle <artifact>!" message, it gives a YAFM referencing A Few Good Men (presumably "You can't handle the truth!").

amateur_hour

Ordinary monsters should attack any player monster with the same priority as the actual player.

FIQhack

aosdict

Conduct that tracks whether you ascend with your original pet.

AimHere

Killer bees should hurt even more than they do currently, and their sting should poison 100% of the time, but they instantly die when they sting.

FIQ

Replace the passtune boon with something more useful, since it is only marginally useful to spoiled players. Then, let the Oracle provide the passtune as either a major consultation or as a service. The Oracle can also be used to tell you which prize is at the end of Sokoban.

aosdict, FIQ

Replace the Sokoban rewards with something that is still nice but not AS nice.
Random fire or frost horn
Unicorn horn
Highly charged horn of plenty (but no food generates in the normal levels)
Zoo is now a throne room, so there is now a throne there

aosdict, Setneicum, FIQ

Replace Sokoban with some other game like mahjongg. Instead of a pass/fail, you can achieve a degree of success. Doing really well nets you both the amulet and the bag, doing slightly less well lets you choose, but ordinarily you will get only one.

flump

Wearing gloves prevents you from making touch attacks. Affects monsters too, so monsters that have touch attacks will avoid wearing gloves.

FIQ

Skills should be exercised even when damage output is 1 (but cutoffs would probably need an increase). Skill level cutoffs should probably be rebalanced anyway; for example, it should take longer to train long swords than it does for broadswords, and this could add an extra dimension to weapon choice.

FIQ, aosdict, jonadab

Unicorn horn skill is also trained by curing things with it, and its chance of fixing something increases with skill level.

jonadab

All Sokoban levels add extra spaces to the corridors to let you push spare boulders all the way into the room if you so wish, which lets you handle monsters zapping wands of digging in the doorway or corridor.

aosdict, elenmirie

Polymorph traps always choose a form considered to be "playable" - has hands, or is fast enough to run from threats, or is well-defended enough to sustain damage until transforming back, must have speed &gt; 0 - but you do not re-form with your original HP when your polyform is killed, you merely die.

ais523

Make Elbereth work the same as it did in 3.4.3 for animals or mindless creatures, but intelligent foes won't be scared by it, they merely won't attack in melee.

FIQ

Make instadeaths more consistent with respect to life saving: brainlessness destroys only the brain but cannot be life saved, whereas disintegration destroys everything but can be life saved. One or both of these should be changed.

AmyBSOD

Implement ZAPM super glue, which can be used to glue the elder priest's tentacles together so he can't attack the player with them.

dNetHack

AmyBSOD

The scroll of create monster, when blessed, says "This is a scroll of create monster." and allows you to choose between 0 and 8 monsters to create.

FIQ

The chance of breaking items inside a container by kicking it is based on Str - Dex. The idea is that more force is likely to smash something, but more control will make it less likely.

rikersan

Archons should emit light.

jonadab

When a god decides to give you a gift and you are already wielding a weapon of the same type, the wielded weapon becomes the gift, and retains its original enchantment and beatitude. Erosionproofing is still added if the weapon doesn't have it.

rikersan, aosdict

Nerf the spellbook of identify so that it only type-identifies items (beatitude, enchantment, and charges will not be considered). If you want to learn these things, you must use scrolls of identify. Alternatively, blessed scrolls of identify could be buffed, for example they always give a full identification of everything in inventory, or they identify several additional object classes that are not yet in your discoveries list.
Also could let identify show beatitude at Skilled and enchantment/charges at Expert.

aosdict, jonadab, Porkman

When reading a scroll of identify when confused, you get enlightenment (you're "identifying yourself").

Setneicum, aosdict

High level (maybe only XL 30) monks can get enlightenment by #sitting on normal floor.

Muad

Gnomish characters get some interesting starting items, like tin openers, candles, oil, or cans of grease.

flump

Humans have a slight advantage in their chance of taming creatures.

jonadab

When the game looks up the scoreboard to generate a corpse name, ignore any games that ended in an ascension. Also, make the rndghost function check the scoreboard.

mys, aosdict, raisse

Fire elementals and vortices have a light radius of 2.

jonadab

2-handed weapons can be enchanted up to +7 as normal, but one-handed weapons can only go up to +5. Alternatively, +9/+7.

flump

Elven gloves, which grant stealth and can be enchanted to +7.

flump

Monsters should not be able to unlock, open, and move into the space of a door all in one turn, or move and eat in one turn.

aosdict, FIQ

Eating brains recovers magic power instead of satiation.

Tarmunora

Give a YAFM when confused and trying to read a scroll of blank paper: "Being confused, you mispronounce the lack of words..."

aosdict, ais523

Banana darts, which can be thrown around corners.

Grasshopper

Blessed charging can select a nonmagical instrument, converting it into a (uncharged?) magical version of the same instrument.

flump

You can break and destroy a loadstone in inventory by applying a pickaxe to yourself, or #rubbing the pickaxe on the loadstone.

aosdict, ais523

Several things relating to making the upper dungeon feel more "eroded" or exposed to the elements/other adventurers, in keeping with NetHack flavor that other people have been seeking the Amulet:
Falling rock traps on shallow levels come "pre-disarmed", which is to say that they have already been used up and so should consist of a pile of rocks on the ground underneath a falling rock trap with no rocks left in it.
Rolling boulder traps on shallow levels generate without boulders or with out-of-line boulders.
Traps with ammunition can have a few pieces of that ammunition lying on the appropriate space.
Dilapidated armories.
Monsters on these levels are likely to generate with zero-charge or low-charge wands or other items.
Fewer items lying around.
Randomly destroyed walls.
Fake bones piles (see below).

Chris, aosdict

Falling rock traps are flavored as unstable ceiling (so that the flavor doesn't get weird for situations like large open levels) and the message changed accordingly. Alternatively, create a separate unstable ceiling trap for that purpose.

ais523

In the uppermost levels of the dungeon, add (non-guaranteed) fake bones piles which contain starting equipment from some role. Gear is eroded or biased towards negative enchantment, most magical items are removed, and perhaps one or two non-starting items are added. Then the whole pile is mostly cursed as usual.

Chris

New special room "rat nest": generates very high in the dungeon, and contains some r, some eroded/negatively enchanted armor, and some comestibles.

Chris

Minor special feature of a level "jackal kill": a corpse of a playable race surrounded by a few jackals. If fake bones piles are added, make this a fake bones pile with "killed by a jackal" on the headstone.

Chris

Stick some orc corpses in Orctown, because they can't have defeated the entire town without any losses.

flump, aosdict

Tourists start with a leash.

Webmant

Certain monsters (intelligent ones like Elvenkings that are smart enough to realize you probably will kill them) turn peaceful or generate peaceful depending on your XL.

statuesurfer

If an undead monster tries to put on an amulet of life saving, it will be either undead turned or destroyed, or brought back to life.

FIQ

Rangers start the game with all types of bows and arrows identified.

rikersan

Yumis are treated as "very well-crafted bows", and allow elf or orc multishot to be used with them (as opposed to the current where you need to use an elvish/orcish bow). The Longbow of Diana is now a yumi.

flump

Rather than giving Monks a flat -20 to-hit for armor, base it on the armor delay - the factor that determines how long armor takes to take off or put on.

FIQ

Covetous warping only works on teleportable levels. It should also count as a regular teleport and cost Pw for the warping monster.

FIQ

Kicking boots damage any monster standing on the other side of a door you kick.

flump

Instead of having Sokoban as a branch, generate occasional Sokoban puzzles in the Dungeons proper. They must not be mandatory.

ais523, raisse

Kicking option or game mode which changes your bump attack into kicking.

flump

Fire and frost horns' damage scales with level.

Luxidream

Fire and frost horns don't shoot rays of fire or cold: instead, they temporarily grant you the appropriate Brand effect (resistance, double fire/cold damage).

Entitas

If a pet nurse is next to you and you choke, it does the Heimlich maneuver on you and you vomit voluminously.

Webmant

Split weaponless conduct into melee-weaponless, ranged-weaponless, and spell-less conduct.

jonadab

Increase the damage of slung touchstones. Slung luckstones are low-damage but have a chance of getting "lucky" hits that do much more damage or instakill monsters.

flump

Reduce the base price of the scroll of blank paper to something low and unique. It should probably cost less than the scroll of identify, but not be incredibly cheap.

ais523, jonadab, FIQ, aosdict

Dwarven characters always see all gold on a level, with the possible exception of gold carried by a monster.

ais523

If the player is polymorphed into a red or blue dragon, they can burn-engrave on the floor with their fire/lightning breath.

aosdict, flump

Rename the potion of gain level to "potion of level up".

ais523

For variants with scrolls of consecration, the confused effect will remove the graveyard flag from a level if non-cursed, and add it if cursed.

various

aosdict

Cursed potions of gain ability give you an ability point in something by taking it away from one of the other scores.

FIQ

If you have autodig enabled and a digging-capable pet is next to a wall or rock square you move into, it will dig that square out for you.

flump

When you fail to write a scroll because you ran out of ink, it will become a "garbled scroll" instead of disappearing. Garbled scrolls can't be read (or possibly they could be read, for a number of generally negative weak magical effects), but they can be re-blanked so the scroll can be written again. This could also happen when you fail to write a scroll by not knowing it. There is a slim chance, probably less than 10%, that you end up writing some random scroll instead of a garbled scroll.

aosdict, flump, Porkman

Artifact pickaxe that blows up the wall instead of simply digging it.

flump, Grasshopper

Polymorphs from polytraps, on monsters, revert on death/time out ala player polymorph. This is to prevent the mines having a balrog forever, or your nice pet archon becoming a leprechaun permanently.

rikersan

Dragons, and probably all MZ_HUGE monsters, can't enter corridor tiles or go through open doors because they're too big. (This would probably mean that corrmaze levels in Gehennom would need to be removed or not generate huge monsters.)

rikersan, aosdict

A blessed scroll of teleportation will allow you to follow monsters that recently teleported away, whether that is a levelport or a normal horizontal teleport.

FIQ

Kicking down a door may damage a creature standing on the other side. This is guaranteed if you are wearing kicking boots.

flump

Reorganize which roles get which special spells, based on the change that every role should always have a 0% failure rate at casting its special spell.

jonadab

To avoid the annoyance of disrobing in a closet to cast utility spells, add a bit to spellbooks that represents whether it is a non-combat, utility spell. Such spells have a much reduced armor penalty, but take several turns to cast.

aosdict, flump

The demon lords take no interest in you until you are on the ascension run with the Amulet. At which point they attack.

flump

Eating a shimmering dragon has the effect of quaffing a potion of wonder.

FIQhack

flump

The Oracle stands on a neutral altar, but killing her sets your luck to -10.

flump

Maximum HP depends totally on three factors: function(role, race, XL) + function2(XL, Con) + (all bonuses or penalties from other sources, like nurses, full healing potions, fire traps, etc), with some diminishing returns on the third factor.

flump, aosdict, jonadab

Pets get a speed increase of (Cha + 6).

flump

Add a message for when the player first satisfies both conditions of having teleportitis and being able to teleport at will.

flump

Arch-liches sometimes generate with potions of unholy water in their inventory.

flump

The spellbook of cure blindness can be read while blind.

FIQ

Water walking boots give you the same speed as speed boots if you are standing on water or a fountain.

flump

Multi-level shops, presumably with multiple shopkeepers or one shopkeeper that follows you to whichever level you're on.

ChrisE

Giant characters or characters polymorphed into a giant should have a boosted carrying capacity.

FIQ

Wands of digging kill any monster made of earth instantly.

deadnoob

The ascension run through the Dungeons of Doom (the instant you come back into your god's sphere of influence) is trivially easy: your god will regularly smite any enemy that dares attack you, and will ignore prayer timeout when answering prayer (but only to fix problems; if timeout is not 0, the god will not grant you any boons.) However, once you reach the Planes, the other gods step in and start interfering with the god so that they can't directly help you anymore. These other gods don't want to kill you since you're still bringing the Amulet closer to them. But when you reach Astral, the other gods will do all they can to kill you, relieve you of the Amulet, and bring it to their own high altar. Your god sends you several A (might be Aleaxes, ki-rins or possibly even Archons) instead of just one, but you are now faced with elite teams of player monsters, priests, and A sent by the other gods, who have amulet-stealing attacks. The gods' struggle to each get the Amulet manifests in all sorts of ways: disintegration beams blasting at you but being redirected onto a hapless monster nearby, inventory cursing, lightning bolts, resurrecting the corpses of dead player monsters or priests, and so on.

aosdict, ChrisE, Wooble

Remove the [yn] prompt for both looting and untrapping. Also maybe streamline the "You carefully open the box... --More--"

mtf

Energy regeneration should cause you to hunger faster.

AmyBSOD

If you get another role's quest artifact through bones or wishing, player monsters of that role will gradually start to be spawned of increasing difficulty who pursue and hunt you down because you are now their quest nemesis.

FIQ

Split containers into a dedicated object class, whose symbol is [. (Mimics can still be [ because the traditional disguise of a mimic is a chest.)

puck

Reduce the level of the spell of create familiar to 2, and give it a dedicated list of summonable monsters based on skill level: Unskilled creates only kittens and little dogs, Basic will pick a random non-fully-grown dog, cat or horse, Skilled will not create kittens, ponies, or little dogs but otherwise will choose any d, u, B, or f that isn't a unicorn. Expert will choose from the Skilled list, plus any q or w. If not doing that, as a more minor change, don't create any monster that is always hostile.

FIQ, jonadab, flump, rikersan

New object property, burden. Makes the item heavier than it is normally. Generates cursed 90% of the time.

FIQhack

rikersan, FIQ, jonadab

Dragons can cast spells.

bug_sniper, Grasshopper

In the last level of the Dungeons of Doom (normally the Castle), the powers of your god and Moloch are approximately equal, and prayer may or may not work here. (The Valley is strictly Moloch's territory.)

aosdict, FIQ

Valkyries have some drain life power, as they are "choosers of the slain" in Norse mythology.

flump

Wishing for an artifact drains two charges from a wand of wishing. If it's a wrest wish or from a source that only gives one wish like a djinni, you merely get the base item type instead.

jonadab

If racial shopkeepers are implemented, they give the player discounts. This could be in the form of a direct buy price reduction (must be capped at 50% of the base cost though to prevent farming) or treating the player as if they had higher Charisma. If the shopkeeper hates your race (for example, elves versus orcs), they will also block the entrance to the store as if you were carrying a pickaxe.

rikersan, aosdict, jonadab, Webmant

Valkyries offering fire giant or frost giant corpses get double the sacrifice value. Possibly this could be generalized to other roles sacrificing "enemy" monsters.

Jendic, aosdict

Sunglasses that block gaze attacks when worn; this should possibly have some downside like limiting vision radius. Also protects versus being blinded by flashes of light from things like lightning bolts, cameras, and yellow lights.

statuesurfer, aosdict

Add a message for a monster you can see that polymorphs via a polymorph trap (or, come to think of it, any source, like the player zapping it at them).

aosdict, jondab

Object properties are more likely to appear on poorer weapons and armor.

flump

Change trap symbols and colors to be more unique: holes should go on their own glyph, level teleporters should be ^, trap doors are ^.

FIQ, jonadab

Archeologists should be immune to rolling boulders.

HTTPS

Lions and tigers have a small chance of being pacified if you apply a whip on them.

jmr

Valkyries can fly at will with the #fly command, but it costs Pw per turn/flying action to maintain.

flump

Aquaman role/race, which starts with magical breathing, a +1 trident, and an oilskin sack. Only regenerates health when in water. If a race, should be able to walk around on dry land (so merfolk are probably out, perhaps merlings or half-merfolk would work). Can drown surrounding enemies. Starts with scrolls of flood.

Luxidream, mdlp0716

Dragonbane gives 100% reflection versus dragon breath.

FIQhack

rikersan, flump

Erosionproofing projectiles greatly reduces their chance of breaking.

rikersan

You are not asked "Pay whom?" if you are standing inside a shop.

Andrio

New type of book "encyclopedia":
Hardback book when unidentified, base price 300.
Nonmagical and always polypiles into a blank spellbook.
When read, it adds the appearance of some unknown magical items (1d4 if blessed, 1d3 if uncursed, 1 if cursed, plus 1 if you are an Archeologist) to your discovery list.
It doesn't disappear when read, but will set a flag that prevents its effects from happening again. This flag will be cleared when creating a bones file.
Archeologists start with a special blessed encyclopedia (using a different flag), which is their research (the starting one comes pre-read and isn't useful to this character): reading an unread archeologist encyclopedia gives the message "These seem to be an archeologist's notes. You pore over them intently.", and type-IDs two unknown scrolls, rings, amulets, and wands, and puts two blessed scrolls of magic mapping into your inventory.
The Archeologist home level contains another encyclopedia.

Luxidream, FIQ, aosdict

If the player starts the game with some random objects type-identified but not in inventory, use a different ID state so the player can have them type-IDed when they come across those items, but they can't startscum for "good" discoveries because the discoveries won't be known at the start of the game.

Luxidream, flump, FIQ, Entitas, aosdict

If you end the game by ascending, you get a fixed score instead of one based on the maximum dungeon level reached. Complementary YASI: this fixed score is zero, so that true zero-point ascensions are possible.

aosdict, raisse

Monsters can move through secret corridors as if they were normal floor, and use secret doors as if they were normal doors (even unlocking them if they have a tool). If the player sees this happening, the corridor/door is made unsecret.

AmyBSOD, aosdict

Wizard-mode ability to wish for "generic ascension kit", which instantly gives you (and auto-equips?) a bunch of gear for an ascension kit.

flump

If you have all three invocation items and have not yet performed the invocation, the Oracle always gives you the message about going to the bottom of Gehennom and performing the invocation. If you have the Amulet, she will give you an otherwise unreceivable message about continuing upward through the Elemental Planes.

aosdict, ais523

Throwing a tin of cockatrice meat at a monster who will normally eat through the metal will instantly stone it, if the monster is stoneable.

Zaha

New msgtype intended to be even stronger than msgtype:stop, perhaps called msgtype:paranoid. Requires the user to type "yes" before continuing.

Deuce-Zen

The Master Assassin offers you the Bell of Opening if you will leave him in peace and let him keep the Master Key. If the player wants to play a chaotic good rogue, they are able to go back and kill the Master of Thieves (without immediately being kicked out of the quest), after which the Master Assassin will give you the Master Key.

aosdict, Webmant

Interface option to shorten "blessed", "uncursed" and "cursed" to three letters so that you get more use out of the inventory sidebar.

flump

Make monster stunning work like player stunning: it moves randomly and may cause them to miss turns.

flump

Ogresmasher doesn't need bonuses versus ogres, or confer beneficial properties. It is simply an oversized sledgehammer with such terrible crushing power that it splatters anything it's swung at. On top of modest damage bonuses, it has chances to instakill sufficiently small monsters, and may inflict negative status effects on large monsters like stunning or slowness (or bleeding, if that is implemented). Probably better if war hammers are made into two-handed weapons.

Entitas

Resting on a bench regains Pw as well as HP.

Fourk

flump

Don't print a message or interrupt anything when your Pw reaches full while you are maintaining a spell, if you haven't actually cast a spell manually since the last time it was restored.

FIQhack

flump

Zen or illiterate players get spells for free as a prayer boon, instead of spellbooks.

Luxidream

A way to dump the entire contents of one bag into another bag.

Luxidream

Strength should not give a to-hit bonus; the encumbrance system is already there to address that.

Webmant, aosdict, FIQ

The fireball spell's unadvanced form creates a single fire explosion at a targetable square, rather than a ray that explodes, so you can cast it at squares that aren't directly aligned with you.

aosdict, jonadab

Unicorn corpses have a chance of conveying teleportitis.

AmyBSOD

Players polymorphed into nymphs have infinite carrying capacity.

flump

Stepping on a square containing a cockatrice corpse while not wearing boots instantly stones you.

AmyBSOD

Petrification is a contact poison secreted by cockatrices, and only partially stones the body part it touches. If you touch one with your hands, you cannot use your hands anymore, etc.

flump

If the scroll of enchant weapon targets a wielded bow but you have arrows quivered, or you are not wielding anything but have thrown weapons quivered, it may switch to enchanting the quivered ammunition instead.

rikersan

The blessed scroll of gold detection also detects gems, and possibly type-identifies any pieces of worthless glass on the level as well (more to prevent interface annoyance than anything else).

aosdict, rikersan

On Valentine's Day, succubi (or any female seducer) steal candy bars you are carrying, and incubi give you candy bars.

Webmant

Artifact chaotic amulet "Amulet of Splendor": provides every single amulet effect, as well as unchanging-ignoring controlled polyself when invoked. Wearing it conveys life saving (this WILL disintegrate the amulet if used), magical breathing, unchanging, poison resistance, ESP, reflection, strangulation (doesn't kill you due to magical breathing but maybe it makes it so you can't eat food or something while wearing it, or it autocurses), restful sleep, and gender change for as long as you wear the amulet. Base type is a cheap plastic imitation of the Amulet of Yendor.

Webmant, aosdict

Remove the ability of ID scrolls to give a full inventory ID, or make blessed ones give a guaranteed type-ID of everything in inventory. Confused blessed scrolls of ID give a full ID of charges, beatitude, and enchantment on all items in inventory, but NOT type-identification.

Webmant

A Minesweeper minigame where you start in an empty zone with a pickaxe. You can always move diagonally through gaps without dropping anything. The amount of mines next to a tile are represented by rock piles on the ground, and you can throw single rocks to embed them in walls to flag mines. Every mine hit causes an explosion that damages, wounds legs, scatters inventory, and penalizes Luck.

Webmant

Give all roles a warning when they might fail to read a spellbook, but make the numbers involved much less useful than the Wizard's warning. (Possibly, just give players "difficult to comprehend" when success chance is less than 100% and nothing else, and buff Wizard warning to add more levels: "somewhat difficult", "difficult", "very difficult", "extremely difficult").

aosdict, Luxidream

Evil version of the Eye of the Aethiopica: it allows you to cast spells using HP when your Pw is depleted.

Deuce-Zen

Dropping an item on an altar to Moloch may, in some cases, curse the item. Ideally this should not be exploitable, so things like a very small chance per drop of an item would not be good. Maybe tied to object ID number if that can't be exploited.

aosdict, raisse

Change up and add new failure effects of spellbook reading:
Any failure confuses you instead of paralyzing.
The level 5+ confusion effect seems quite tame in comparison to the other effects, so replace it with paralysis.
New effect: book tries to eat you
New effect: level drain
Spell enters your head automatically, but erases your knowledge of one/all of your other spells. (This could be quite annoying and may be better off as an EPI.)
New effect (possible in combination with other effects, and for any book): book curses
Books no longer have a 1/3 chance of disintegrating when failing to read them; instead, a cursed book will always disintegrate.

aosdict, Zaha, Deuce-Zen, Grasshopper

Eating a bag of tricks (as a gelatinous cube) does something interesting, maybe only YAFM, maybe more.

Wooble

Quantum mechanics' hits toggle your speed instead of teleporting you if you have teleport control. (You already know your position, so your velocity must become uncertain.)

Deuce-Zen

Pacifist option, which suppresses attack from normal movement. (You can still attack with the F command.)

Deuce-Zen

The scroll of destroy armor, when confused, cursed, and naked, grants temporary disintegration resistance.

Webmant

Golems hate existence so much that they attack all other creatures, but the other creatures don't hate golems, so they just defend. This is a special case of implementing one-way grudges.

flump

Zombies always try to path in a straight line towards the player (assuming they can see or otherwise are aware of the player), and get stuck on terrain.

ais523

Make the Castle barracks have second doors that open onto the courtyard.

mtf

Soldiers surrounded by other soldiers have higher AC, to-hit, and damage.

mtf

The Oracle now prompts the user to ask a question. Her oracularities now have associated keywords (a many-to-many relationship); if you use keywords, she will select an oracularity matching as many of them as possible. If she doesn't know what you're asking about, she gives you a random oracle. This could even be leveraged to ask about information that's normally hidden from the player; for example, asking about the Sokoban reward or the location of branch stairs.

aosdict, jonadab, FIQ, mtf

The Oracle has the same item as the prize in Sokoban, so you can pay her to tell you what the prize is (because she'll have it with her). This opens up a strategic choice where players can decide whether to kill her and skip Sokoban, or not. She will need to be quite stronger than her current abilities are, with passive attacks that work even at range. Alternatively, she could carry the other Sokoban item, depending on how formidable she is.

Webmant, jonadab, mtf

Elementals fire back weapons you throw at them with additional force (so, usually, additional damage): water elementals in a geyser, fire elementals burning with primal flame, air elementals in a gust, earth elementals in a shower of rocks (or they just incorporate the weapon into themself and become stronger, dropping it on death).

Webmant

Cursed magic whistles send pets away from you. (This is perhaps exploitable with e.g. purple rain strategies on Astral.)

flump

Make object properties a boolean array, not a bitmask, so that the developer isn't limited by the number of bits in an integer.

FIQ

"streak_mode" option. Only allows one saved game at a time.

NetHack 4

mtf

A windowport that allows you to play local sound files when the game produces certain messages.

Deuce-Zen

Barbarian unarmed skill enhances for free when you finish the Quest, get crowned, or reach a certain level.

Fourk

flump

Applying a blessed magic whistle while confused teleports you to one of your pets.

flump

Water elementals deal active water damage to the player, more broadly than rust monsters: blanks scrolls, dilutes potions, extinguishes candles, etc.

Luxidream

Autocursing armor always generates cursed; it is thus perfectly safe to wear any confirmed non-cursed armor the player finds.

aosdict, AmyBSOD

If escaping a prompt would use up an item or charge, re-prompt at least once (or maybe have an option configuring how many times it re-prompts.)

flump

Valkyries only gain wings (and Flying) after they are crowned.

Fourk

mtf

Special room that contains a demon gate in the center. This continually spawns monsters who try to defend the gate; the player has to make it through the spawns to destroy it or block it off. The gate could be implemented as a magic portal to a special challenge level like an ADOM-style vault.

flump, aosdict

Make being on fire a status effect, which deals damage over time. (Other obvious things to make into damage-over-time effects: poison, bleeding/internal damage.)

jonadab, mtf, aosdict

Priests can #offer anywhere (that they can normally, so not in Gehennom), with no need for an altar. (This may be strictly worse than altar sacrifice - maybe it only reduces prayer timeout, not by as much as it would normally, and can't give artifacts or make holy water.)

Webmant, FIQ, aosdict

Other priest benefits: double the chance of receiving a sacrifice gift, increase the crowning chance or chance of a high favor, don't get an increased maximum prayer timeout when crowned.

Webmant

Werebane provides protection from shape changers and immunity to lycanthropy while wielded.

jonadab

Sokoban provides a choice between an oilskin bag of holding and an amulet of reflection and magical breathing. Neither of these is very likely to generate randomly.

FIQHack

flump

Master wand of death kills and enslaves the monsters it hits.

FIQack

flump

The Oracle sells type-identification of any one carried item for a fee.

jonadab, mtf

Shopkeepers type-identify any item they sell you. (This allows the player to type-identify an item by selling it and buying it back.)

jonadab

Rebalance Fort Ludios so that it can realistically only be completed after finishing the Castle. One way to do this is to make soldier AI better, another way is to put the entry and exit portals on opposite sides of the level (or put the exit portal inside the fort), so the player can't return to the Dungeons of Doom when things get hairy. The goal of doing this is to delay a large power spike due to collecting all of its gold until the player is truly ready for it.

aosdict, mtf

Rogues have a 20% (or 10%, or whatever is balanced) chance of stealing a random lightweight item (say, less than 5 aum) out of a monster's inventory with every successful melee hit they make. This chance is increased if they are hitting with no wielded weapon or have no secondary weapon or shield, and maybe should scale with experience level too.

aosdict, jonadab

Monsters who can use items and estimate that they are strong enough will attack crossaligned unicorns to get the horn.

jonadab

When a monster kills a monster that it grudges, it gets some bonus like a small HP boost or a level up.

flump

A level sound for when there is a dragon somewhere on the level.

FIQHack

flump

Bards can sing one song without requiring an instrument.

dNetHack?

flump

Consuming "smoked" meat from a tin may release a djinni. (To prevent farming, tins created by polypiling or from horns of plenty might need to be limited to the homemade-or-rotten that player-made tins can be.)

flump

Samurai can't use Excalibur, because it's cross-culture. The Tsurugi should be buffed to be quite good enough.

Luxidream

Revenant race. Only available for roles you have died playing and didn't leave bones. Gets death resistance and unbreathing from XL1, has an automatic counterattacking kick. Any starting gear is scattered randomly across dungeon level 1. No pet.

Fourk

flump

On the Plane of Water, fire wands and fire spells expand your bubble, and throwing a bag of holding out into the water creates a new huge bubble (as a large but finite amount of the water is sucked into it).

flump

Tinning kits include tin openers implicitly, so if you wield it you can open tins.

jonadab

Wizards who can't cast spells while crowned (permablind?) receive something other than a spellbook of finger of death.

Luxidream

The Heart of Ahriman returns to your quiver when slung. Or at least add some returning sling-ammo artifact.

mtf

New slot for belts:
Belts themselves could be armor or tools, but probably armor. They mainly serve to hold items for quick access. It's not defined whether they are intended to hold an indefinite number of items like any container, or a limited amount. The only problem with making them armor is that they would by default be enchantable for more AC; belts should probably not be enchantable. If it makes more sense that several magical belts would hold charges, tools would be the appropriate class.
Items carried in a belt weigh nothing and are mostly or totally protected from destruction, and using them doesn't take the action it usually takes to get an item out of a bag.
Types of belts could be scroll-holding, potion-holding, wand-holding, ammo-holding (with a possible "endless quiver" item or artifact), gem-holding (to get partial resistances from certain gems), chastity (providing immunity to foocubi seduction) or no special powers but some moderate AC.
One randomized belt description could also provide protection against leprechaun theft.
Randomized descriptions could include: cloth, leather, worn, studded, buckled, braided
Tourists and Convicts also start off with garish swim trunks/striped slacks, which do the same things as Hawaiian shirts/striped shirts. The swim trunks also allow swimming. Both of these protect from instadeath when you sit on a cockatrice corpse.
Belts of giant strength, elven grace, and troll toughness. These increase your Str/Dex/Con either to 25 or by +enchantment (if belts can even be enchanted, which isn't currently defined.)
Swordbelts/sheathes. These allow you to ready an additional weapon or give you an additional weapon slot.
Also see User:Red kangaroo/YANIs/Items#Belts.

ais523, mtf, aosdict, Chris_ANG, Luxidream, RGRN

Monster spell that creates a wall, or possibly just a boulder, to block the hero's progress.

aosdict, Demo, Crawldragon

Fixed crysknives never revert.

jonadab, FIQ

Add a boulder-throwing skill for giants. The skill cap is determined by your role.

Fourk

AmyBSOD

Kicking a lightweight object into a wall will cause it to "rebound" or "clatter" (for wooden objects) off the wall, not just "Thump!". The object might move a couple spaces.

aosdict, Demo

Touchstones no longer count as magical items. (Real-life touchstones aren't.)

FIQ, jonadab, aosdict

Statues block line of sight.

ais523

Rock moles can be tamed by throwing a metal weapon at them, which they will catch and eat.

ChrisE, aosdict

Levels between Medusa and the Castle generate with roving contingents of the Yendorian Army, and have large open areas if they are maze levels.

aosdict, FIQ

Amplification trinsic which is a counterpart to reflection: an attack that hits you will be amplified and continue past you (greater range and greater effects).

ais523

Allow edged weapons to be applied to force open door locks. (They can break like this.)

deadnoob

Bows might break, like boomerangs, when you whack things with them in melee. (Will require an AI rewrite so 500 gnomes don't break their bows on you.)

twrk, aosdict

q class monsters should have their difficulty rebalanced to at least roughly reflect their damage output; mumakil are the strongest q of all and have one of the lowest difficulties.

StatueSurfer

New unaligned artifact dagger Almagest: uses the powers of scrolls to augment itself, and bears a scroll label signifying which scroll ability it is imbued with. Opinions vary on whether this label should be randomly generated by the dagger (and the player may choose to read it, upon which it gives the uncursed scroll effect and disappears for 1000 turns, eventually returning with another label) or whether the label should be deliberately imbued by the player by #rubbing it on a scroll. It gains +d4 to damage and +d4 to hit when it has an inscription.
There are additional special effects if the player has formally IDed the scroll:

Identify: 25% chance of probing
Light: +d6 to undead, light source
Enchant weapon: +d4 damage
Enchant armor: gives 3 points of AC when wielded
Remove curse: Protects fully from all curses when wielded
Confuse monster: 25% chance to confuse
Destroy armor: Ignores enemy armor when calculating to-hit
Fire: +d8 fire damage
Food detection: Enemies are much more likely to leave corpses
Gold detection: Enemies may drop small amounts of gold when killed
Magic mapping: 5% chance of activating clairvoyance on hit
Scare monster: 15% chance to scare on hit
Teleportation: 10% chance to randomly teleport on hit
Amnesia: Extra mindflayer tentacle attack, no effect when read
Create monster: 5% chance for create familiar effect on hit
Earth: 5% chance to create boulder over enemy
Taming: 5% chance of charm monster effect on hit
Charging: Does 2x Pw damage and adds it to your own, 5% chance of cancellation
Genocide: Instakills as Tsurugi, +1 damage
Stinking cloud: Permanently poisoned
Punishment: Weighs 100, deals +d12 damage. Autocurses and triples alignment losses.

Luxidream, aosdict, FIQ, ais523

Luck ideas:
Luckstones don't remove luck timeout, they merely extend it.
Luck is much less controllable, impossible to get any clues about except through enlightenment, and various random events (like what?) can give or remove luck. A skilled player would know how to bias the odds towards luck-increasing events. Controllable sources of gaining luck like sacrifice and throwing gems at unicorns are removed. It no longer times out.
The luck timeout rate is less predictable, and a luckstone will help but it might still time out quickly if the RNG hates you.
The base number that luck times out to is equal to the total number of luckstones in your inventory (so carrying 2 noncursed luckstones means luck times out to +2). Luckstones' weight is increased.
Remove luckstones in favor of an amulet of luck. Luck timeout can no longer be slotless.
Luck times out at a rate of 1 point per (600*(number of luckitems + 1)) turns.
Do away with luck timeout entirely in order to make it impossible to micromanage luck. Luck is now conferred entirely by luckitems. The problem with this approach is that NetHack has about two ways to gain timing-out luck and many, many ways to lose it.
Luck can be gained by enchanting luckstones.
Different types of luckitems which stack with other luckitems but not with each other, like a four-leaf clover you can get from leprechauns.

aosdict, jonadab, ais523, mtf, Jendic, FIQ, greqrg

Failed artifact wishes give you the base item type instead of nothing.

rikersan

Assuming a wand of stone to flesh is added: with high skill, it changes diggable walls into huge chunks of meat.

FIQHack

aosdict

If hovering over a trap door and zapping an opening beam downwards, the trap door becomes a hole.

jonadab

The scroll of scare monster, on the ground, will do a check versus monster magic resistance before it actually scares them.

aosdict, statuesurfer

Add a mechanic like applying a scalpel to a monster to give healers a source of healing that isn't tied to magic.

Demo

Tabbing to auto-attack monsters (at range or at polearm range).

Pinkbeast

A type of boots, perhaps high iron boots, that protects fully against xans.

ChrisE, aosdict

When tame shapechangers polymorph, they attack creatures based on their current monster level (or perhaps the maximum of their current level and their new form's level), not blindly use the new form's level.

aosdict, ChrisE

Have different summon nasties lists, based on what monster is doing the summoning. If a demon summons, you get mostly demons; if an undead summons, you get mostly undead. Needs some more lists for lawful summoners like titans or Archons and Quest nemesis spellcasters. The current list is kept for the Wizard of Yendor.

jonadab, aosdict

Artifact bullwhip that grants extra damage against tigers and other animals, and grants better passive pet-control effects.

jonadab, aosdict

Make magic cancellation visible in the status bar.

FIQ

You can walk diagonally into or out of an open door if there is also another open door adjacent to both your starting and ending location.

FIQ, aosdict

Applying or invoking the Candelabrum with insufficient candles prompts you to attach more candles to it.

ais523

Potions that you can drink from multiple times.

ais523

Role-specific artifacts given to you only when you are crowned.

FIQ

Single-level branches whose portals, found in vaults, disappear after one use; they are subdivisions of the Magic Memory Vault, and modeled after ADOM "vaults". These are basically challenge levels, smaller and less rewarding than Fort Ludios (the master branch), that contain some nice loot and harder-than-usual monsters. Portals to them can also be found in vaults in Gehennom.

aosdict, ais523, mtf

Fort Ludios is a visit-once level: once you leave by the exit portal, the Dungeons of Doom portal disappears and the level becomes inaccessible forever. (Maybe if you leave any of the invocation items or the Amulet there, the portal refuses to let you out so the game doesn't become unwinnable.)

ais523, aosdict

Convert some of the Gehennom filler levels into ADOM-like greater vaults that contain many challenging monsters and an artifact.

mtf

When you try to loot a locked chest but have an unlocking tool, automatically apply it and then continue to loot the chest.

mtf

Keys only work on locks in one dungeon branch.

ais523

Restore the Amulet Delivery Service to the game: demon lords in the Sanctum, but not the Wizard, will fight the current holder of the Amulet of Yendor for it. Only do this if lugging a demon lord down to the Sanctum is considerably harder than just fighting through the Sanctum is itself, and no demon lord is actually guaranteed to win against the High Priest.

aosdict, ais523

Mjollnir confers shock resistance.

aosdict, Luxidream

Gods may grant a saddle as a sacrifice gift and unrestrict riding skill.

FIQ

Make death magic resistable by an amulet or ring. Possible names and corresponding exact effects vary:
"life protection" (bad name, life saving is very similar)
"unliving" (makes you not count as living and life saving won't work)
"undeath" (actively makes you count as undead, you are vulnerable to turn undead effects and lawful gods may be annoyed at you)
"versus death magic"

ais523, FIQ, jonadab

Artifact shield of reflection that reflects thrown or fired projectiles.

Demo

Ranged attacks can be directed at the . space. If this ends up killing you, the death reason is "shot [him/her]self in the foot".

AmyBSOD

New role, the "Renegade", where your goal is to destroy the Amulet of Yendor. You start the game with the Bell of Opening (you found it as a child and had your mind opened), you are unaligned so all the gods hate you. No quest.

NCommander

When a monster decides whether you are peaceful and makes race or alignment checks to do so, they do it based on polyform, current alignment, and when they first spot you as opposed to when they are first created. If the player polymorphs into an orc and some other orcs are hanging out in an unexplored room across the level, they should be peaceful to the character as long as the character is polymorphed into an orc (but will turn hostile when she changes back).

aosdict, FIQ, Chris

When you violate a spirit's taboo, make it explicit which action broke it, either through the spirit verbalizing it or in some other way.

dNetHack

NeroOneTrueKing

In variants with reviving undead, you can apply a weapon &gt; at a dead zombie's corpse to destroy its brain (for simplicity, this destroys the entire corpse) and prevent it from reviving. This may take several turns.

aosdict, FIQ

If you are wearing silver armor without some sort of protection layer like a shirt underneath it and you contract lycanthropy, you immediately take silver damage all over your body and die.

GruntHack

aosdict

In variants that have multiple selectable Sokoban prizes, one prize is multiple random rings and a random amulet, but there's no way to see what they are without sealing off the other prizes.

aosdict, Tangles

Paper bags that are a container but disintegrate when wet. They can generate with a potion of booze inside.

Grasshopper, aosdict

If you throw a bell (or possibly any non-cloth item), it makes a clanging or clattering noise that wakes monsters.

Grasshopper

Add pegasi, lawful u-class monsters that fly, have a slightly higher base level than a warhorse, and speed around 25. Might be tameable with vegetables, or only blessed vegetables, or one certain veggy food, though.

FIQ

Find some justification for making the flavor of Sokoban a branch where the ceiling collapsed and opened up pits and dropped rocks everywhere.

ais523

Eating a cockatrice corpse only petrifies you 85% or so of the time, the rest of the time it "tastes like chicken".

jonadab

If you attempt to put on a helm of opposite alignment in the Astral Plane, your god is angered and disintegrates it off your head before your alignment changes.

FIQ

Change the sandworm tooth material to MINERAL (they are crystalline, not bone) rather than having no defined material.

aosdict, jonadab

H-class monsters are tall enough to stand above water, and don't drown in it. Or maybe they only drown on water spaces completely surrounded by other water.

aosdict, rchase

Squares containing burning candles ignite flammable monsters that move onto them. However, such monsters should stay away from spaces they can see have a burning candle.

Wayward_Vagabond

Charging a potion of fruit juice turns it into a potion of see invisible. Dipping fruit juice into confusion turns it into a potion of booze.

aosdict, Deuce-Zen

There is a cap on the number of smoky wish-granting djinni that can appear in one game.

jonadab

You can mark certain squares as "ignored" so that when you walk over them they don't show you the items on it.

ChrisE

Elves get low-light vision, which doubles the radius of light sources, rather than infravision.

ais523

Higher pickaxe skill increases digging speed.

bouquet, K2, jonadab

An option to disable statue glyphs rendering as their monster symbol.

FIQ

Wands may generate pre-recharged.

ais523

Trap failure should be based on stats like Dexterity and maybe role and XL, not Luck. Also, success chance of writing an unknown scroll or spellbook should use Intelligence and not Luck.

ais523, aosdict

Revamp Astral so that the challenges to player mobility, options, and time don't all depend on being crammed in by monsters. One idea is to have spellcasters that summon force fields / temporary walls to block your progress.

aosdict, jonadab, mtf

As part of artifact rebalance: guaranteed sacrifice gifts should probably not be ascension kit quality gear, since otherwise sacrificing for such gear becomes a dominant strategy. (Most important for weapons; you don't want to be able to obtain a weapon early that will obsolete all other weapons in the game.)

aosdict, mtf

Add "You vaguely feel a vague sense of vagueness" as a hallucinatory message.

rumflump, jonadab

Remove the scroll of stinking cloud in favor of a potion that when shattered releases a stinking cloud. Drinking this makes you vomit or become ill.

aosdict, FIQ, jonadab

Jumping either acts on a timeout and can't be done right after a previous jump, or else it takes a full turn's worth of movement points (more so than the existing mechanic of reducing movement points to 0).

aosdict, mtf

More marginal corner-case uses for gems (similar to the amethyst/booze interaction):
Throwing a diamond (or a diamond ring) at an opposite-sex foocubus will tame it.
Rubbing an amber stone generates electricity, perhaps giving you a static charge that will add a bit of damage to your next melee attack.
Hitting a demon with obsidian traps it as if it were a bear trap: it can't move or teleport, though it can still attack. This also destroys the obsidian.
Moonstone allows you to control lycanthropic shapeshifting. (Moonstone exists only as a ring in vanilla, not as a real gemstone.)
Rubies and sapphires provide some very marginal protection against cold and fire respectively.

firemonkey, aosdict, elenmirie, jonadab

Differentiate between poison, which comes solely from ingesting it, and venom, which comes from getting toxins in your bloodstream from a bite, claw, or sting. Monsters like spiders can be both poisonous to eat and venomous when attacking.

Menche, jonadab

Scale the spell of charm monster by skill as follows: unskilled attempts to pacify one adjacent monster, basic attempts to pacify all adjacent monsters, skilled attempts to tame one adjacent, and expert attempts to tame all adjacent, all subject to monster magic resistance.

jonadab

The cursed potion of see invisible removes any see invisible intrinsic that the player has.

NCommander

Implicitly #untrap a chest when opening it (check it once for traps, not enough to guarantee there are no traps, but if one is found, prompt to attempt removing it.)

nht

Change the confused effects of the scroll of punishment: blessed mollifies your god if angry, uncursed increases anger by 1, cursed increases anger by 1 and your god smites you.

jonadab, aosdict, FIQ, splatpope

Add hallucination effects to (many, perhaps all) scrolls:
Scroll of punishment: changes your Luck based on scroll beatitude

jonadab, FIQ

Demon lords that accept a bribe don't actually go anywhere. They get out of the way if they were previously in the way, but otherwise they have their movement points set to 0 for as long as they are peaceful, and don't warp to you.

aosdict, Demo

Change the definition of polyselfless conduct to "You have never intentionally changed form." If you step on a hitherto unknown polymorph trap and have an uncontrolled polymorph, the conduct is not broken.

greqrg, aosdict

Set the minimum dungeon level for polymorph traps to a deeper level, to perhaps 12 or 15. Polymorph traps now polymorph you in spite of magic resistance, but you can acquire some property (not as strong as polymorph control) that makes it much more likely or guaranteed that you will polymorph into a form that will preserve your armor and your hands.

FIQ, aosdict

Make monster sleep work more like player sleep, where being attacked / taking damage is quite likely to end the sleep. Then sleep is not basically a duplicate of paralysis.

mtf, FIQ

Change the color of the player's @ when their HP gets low or decreases sharply.

ais523

Ammunition that is +X will break if and only if it scores a hit on a monster above a certain difficulty. The formula suggested was that it can only break when 5X+3 &lt; difficulty, but this is just a wild guess at the numbers and isn't balanced.

ais523

Add a monster species flag for "zombifiable", and track zombification or mummification as flags on an individual monster, removing the need for Z or M to be separate classes.

aosdict, jonadab

Buff zombies, to make them more of a threat. Import FIQHack zombification (a zombie bite will place you 90-100 turns away from turning into a zombie, each additional bite decreases the timer by around 10 turns, but it will go away by itself if the timer doesn't dip below 40); boost their difficulty, but keep their HD low; allow them to revive themselves less frequently than trolls, but also revive themselves whenever another zombie steps over their corpse.

aosdict, jonadab

Mummies have a curse item attack that would probably make them not fun to have in their current quantities. So mummies are not randomly generated; they appear in graveyards and some special levels like the Catacombs and the Archeologist quest, but otherwise do not appear.

jonadab, aosdict

You can attack yourself by using the F command and selecting . for yourself.

APic, ais523

You can use whole object classes when using the numeric prefix with the D command, e.g. D 1&nbsp;? will drop 1 of each scroll you are carrying.

rumflump

Rust traps' item rusting is delayed. You can use a towel to prevent a wetted item from rusting.

Deuce-Zen

Special room that is lined (not filled) with statues of you, and contains no monsters, items, traps, or anything else interesting. All doors in contain traps that will make them lock behind you. Intended only to make the game more creepy.

aosdict, ais523

You occasionally get an alignment bonus if your alignment record is negative and you are Weak, because you are doing hunger penance. (Possibly only works for lawfuls, since chaotic gods are unlikely to approve of weakness.)

aosdict, Deuce-Zen

Challenge rooms that occasionally get embedded into Gehennom levels. They are sealed off somehow, perhaps with solid stone you need to dig through to enter. They are not intended to be required, and contain some sort of reward. Rooms might include:
Demon den: one or more demons guarding some gold and gems. (In a cavernous Gehennom, we can expect that most of the mineral wealth has already been mined out by millennia of demon activity.)
Seminary of Moloch: contains an altar to Moloch, one peaceful priest of Moloch, and multiple hostile priests of Moloch.
Fake wizard towers: the standard 7x7 footprint consisting of moat and tower, with an amulet in the center of the tower (possibly EPI: this could be a fake Amulet of Yendor), and a few monsters inside the tower. The flavor basis for these is that they are the Wizard's earlier settlements.
Hostage room: contains a lot of monsters guarding a prisoner or player monster hostage. The reward here might be that the monster auto-tames when freed.

jonadab, aosdict, mtf

Every spellcaster should have its own list of spells it can cast. (Archons and possibly nalfeshnees should be casting clerically aligned spells rather than mage spells.)

jonadab, aosdict

Summoning spells examine how many summoned monsters are currently on the level, and cap it at some point so the level can't fill up with more and more summonstormed monsters.

jonadab

Reflavoring of Heaven or Hell mode: everything explodes when it gets hit by anything.

aosdict, jonadab, Demo

Very powerful artifact armor that cannot be removed without dying. If you take it off, polymorph out of it, or have it removed by a monster, you die.

Demo

The Oracle centaur statues may contain sizeable piles of ranged ammunition, particularly arrows and crossbow bolts.

aosdict, FIQ

Resolve the problem of having to double-enchant launchers and ammo and get double bonuses in one of two ways:
Make the double bonuses at higher cost a feature of ammo-based fighting. You can now enchant rocks and flint stones, though all randomly generated ones must be +0.
Make ammunition unenchantable (but still fooproofable), and the launcher enchantment affects to-hit and damage bonuses like normal. This is good because it means that ammo stack management is less annoying.

aosdict, mtf, luxidream

Random chance to get lead poisoning while quaffing from a sink. This abuses Int and Con.

wheals, jonadab

Intelligence can be abused and exercised, but unlike other stats, exercise will never bring it above its base value (or the value you have raised it to through gain ability). Sources of abuse: mind flayer brain eating, zombie attacks. Sources of exercise: reading spellbooks, writing spellbooks, writing scrolls.

aosdict, jonadab

You can engrave on walls or doors. Elbereth doesn't work unless you're standing on it. You can read it by standing on the nearest space. Random graffiti, if it generates on a floor square next to a wall or door, may say "Something is written on the wall here." instead of the floor. Graffiti could render as ~ or something similar.

aosdict, mtf

Greased gloves grant extrinsic slippery fingers.

FIQ

If a scurrier selects , or . when asked what to eat, they attempt to chew through the floor.

Fourk

aosdict

Black pudding globs convey only one of the three intrinsics they currently convey (maybe shock resistance), and brown pudding globs convey another (maybe cold resistance).

aosdict, firemonkey

Kicking down doors exercises Str and not Dex.

aosdict, firemonkey

In shops, picking up an item spawns a peaceful monster that vanishes once you pay for the item properly. If you make any attempt to steal, it turns hostile. (The general principle: the more you want to steal, the harder it is to do so.)

ais523

Erosionproof items should be immune to disintegration as well.

jonadab

Restructure Gehennom as follows: the main trunk consists of the Valley, then 5-7 filler cavern/lava levels interspersed with two bribable demon lairs, then the Vibrating Square level (also cavern/lava), then the Sanctum. The Vibrating Square level contains six revealed portals, one of which leads to the Wizard's Tower, one of which leads to Vlad's Tower, and the others all lead to demon lairs in which you can't leave the level until the demon is defeated.

aosdict, FIQ

Merge dart and arrow traps into "missile" traps, that fire a random sort of missile. Also, make such traps store their ammo in the trap to be fired one by one or released when #untrapped, not to be created one by one when triggering.

FIQ

Dart and arrow traps are much more likely to generate if the trap is next to a wall. Alternatively, when generating a dart or arrow trap, look for a wall tile in line within 3 squares that contains the launching mechanism; if no such tile exists, the trap cannot generate. The player must then untrap the wall square, or dig it out, to remove the trap.

aosdict, Tarmunora

Your quest leader can heal you if you come to them injured or sick.

bug_sniper

Entering the Valley and entering the second level of Gehennom (as well as possibly entering other branches) give the hero an automatic level up.

ais523

Occasionally and temporarily (perhaps as a form of harassment), the Amulet becomes massively heavy.

ais523

Cave-like or cavernous levels, like the Mines and the Caveman home level, spawn bats fairly often.

aosdict, FIQ

Strictly separate the AD_SITM and AD_SEDU stealing attacks (hostile theft vs. charming to hand over an item), and remove the is_animal checks from the stealing code.

FIQ

Rename AD_SEDU to AD_CHRM because it's not really seduction.

jonadab, aosdict

Nazgul cannot be killed "incorrectly" (unclear on what this needs to be, perhaps stabbing them with a barrow-wight's knife, or being female). If you happen to kill one incorrectly, it will be killed without giving experience and its inventory will be deleted (minus unique items). The Nazgul born counter then ticks down by one, so it can be spawned again elsewhere by the normal mechanism.

Deuce-Zen, Wooble, aosdict

The number of levels a trap door will take you down is deterministic for every trap door. Possibly also extend the trapdoor and migration code to allow deterministically placing coordinates of things that fall through a trap door as well.

aosdict, StatueSurfer

Ignore missing "of", "the", and the like in wishes.

rumflump

Saltwater, intended as a nerf for "just dilute most potions":
Potions of saltwater behave exactly like potions of water, except that they cannot be used to bless or curse things. Holy (and unholy) water must be pure.
All in-game sources of water except for magic fountains are saltwater. Diluting potions in them will yield only potions of saltwater.
Can also get pure water if a unicorn horn dip would already result in water.
Not specified what cancelling potions should do.
Alternatively, make saltwater not an actual potion, and just use saltwater as a flavor reason for why the player can't intentionally dilute potions to water. (Can use a separate flavor argument, that potions are generally corked while not used, to explain away the lack of dilution for water damage.) Also, make most potions cancel into non-water base potions (such as confusion and hallucination to booze), with the notable exception of polymorph. It's also harder or impossible to get water from random alchemy or polymorph.

aosdict, Luxidream, FIQ, ais523, mtf

Modify Sokoban maps so that a monster can never get stuck in an awkward place except by the player doing something foolish. Possibly make the corridors leading to the goal double-sized or have alcoves off to one side where a monster can move.

ais523, FIQ, aosdict

Monsters in groups should always spawn with the same affiliation (tame/peaceful/hostile).

FIQ

"Coffin" boxes should use corpsenm instead of spe to represent whether they contain a vampire. Useful because it could be used for other creatures (including Schroedinger's Cat).

dNetHack

aosdict

In Orcish Town, there should be peaceful orcish racial shopkeepers with actual shops (who will happily sell you the human shopkeeper corpse on their floor.)

SporkHack

Luxidream

When you attempt to interact with (or possibly explicitly search) a door or container, you get "There [are no traps / is a trap] on this [door / container]."

aosdict, FIQ

Change Vorpal Blade to do very high damage (on the order of x3 or x4) when it critical hits, in order to remove YAAD potential in monster hands. Replace the decapitation message with "Your Vorpal Blade goes snicker-snack!" Find some other message to replace this existing message (when you are neutral crowned but already holding Vorpal Blade).

FIQ, aosdict

Hallucination should cause statues to be seen as monsters that don't move and perform nonsense actions.

jonadab

When wearing gauntlets of power, thrown javelins (or other spear-likes) continue flying after hitting monsters, and may damage monsters standing further back.

rumflump

Flesh-eating scarab beetles: they may reproduce every time they bite you.

jonadab

In order to make extrinsic regeneration scale better, it acts as a multiplier to your natural regeneration rate. x2 is an option but may be too high; x1.5 might work better.
Another idea is to make it so that regeneration gets better the closer you are to dying of HP loss, formally: if current HP = X * maxHP, regeneration will heal you at a rate of (2 - x) times its normal rate.

aosdict, FIQ

Reach gloves: let you pick up items from adjacent squares and grapple monsters.

Luxidream

The ability to chat with intelligent pets and give them basic strategy directives, such as what type of attack they should be favoring.

Luxidream

If the player sits on a throne after being crowned, even in non-royal polyforms, they get the royalty message.

Deuce-Zen

A Minetown (or some other town) minigame based around classic survival/area defense games:
Takes place in a smaller-than-Minetown square walled area in a large open part of the mines.
Orcs, with a very high spawn rate and an increasing difficulty modifier, appear around the edges of the map.
The walls will block the weakest and the unequipped from entering the town proper, but it won't be good once orcs start showing up with pickaxes and ladders.
To prevent the orcs from building up a horde, there are some weaker points in the walls, maybe a gate they can try to bash down or an unrepaired breach. These must be defended with manpower and all the traps you can think to lay.
Orcs grudge everything inside the town, and vice versa; meanwhile, nothing in the town is hostile to you.
Shopkeepers sell you items from their limited inventory at very cheap prices.
There are watchmen who can hold back an incursion, but they'll eventually fail if the player isn't able to get there in time.

aosdict, Deuce-Zen

More variety in ranged unreflectable elemental attacks, as a sort-of-nerf to reflection (all ranged elemental attacks currently in the game are reflectable). For instance, have enemies shooting fire arrows at you.

ais523

Make more potions effective for throwing at monsters, first by making the vapor effects hit more than just whoever they were thrown at (i.e. splash effects), and then by making more potions have a vapor effect that affects monsters.

FIQ

Diluting full healing potions turns them into undiluted extra healing; diluting extra healing turns them into undiluted healing.

FIQ

A demon lord who lives in Gehennom who you can sell your soul to in order to gain levels. This will have drastic effects on your score (or something) at the end of the game.

dNetHack

aosdict

Monster flag M3_TELWITHU. Monsters with this flag (examples: quantum mechanics, some devils) will follow you when you teleport horizontally.

aosdict

Use 3.6.0's randline function to trace a path between the upstairs and downstairs of each level. Along this path, remove or relocate any traps, and (in early levels, perhaps up until the Oracle) convert any secret doors or passages along the path into regular ones.

aosdict, jonadab

Fountains, sinks, and other dungeon features can generate inside shops. Using them in any way incurs a usage fee. Destroying them incurs a larger charge to be paid immediately, or the shopkeeper will get mad.

AmyBSOD

Polymorph potions affect all monsters adjacent to where they shatter.

bouquet

Remove the scroll of genocide, or else institute some awful (divine?) punishment for genociding monsters, because it is a heinous act. (This would help with symmetry for monsters using genocide.)

aosdict, FIQ

Thrones have an affiliation with a monster. Only the affiliated monster can sit on it and use it. It starts out as the king monster generated on the throne. If the monster dies, its killer becomes the new affiliated monster. This would need some flavor for why the king doesn't just sit on it and use it until it vanishes; there are a few possible ways to handle that. One is that though the throne effects are good, the king is flavored as not wanting to lose the throne. Another is that throne rooms will start empty except for the king and maybe a couple guards, and the king does in fact use the throne's powers against you (without risk of it vanishing since he is the original owner, or something).

FIQ, jonadab

Define boulder weight so that giants can't carry an infinite amount of them.

GruntHack

K2, jonadab, aosdict

When a boulder drops on a tile containing another boulder, it tries to roll to an adjacent tile. If it can't (because all adjacent tiles have boulders or can't have boulders), it drops as a second boulder like normal.

jonadab

New object property "identification". Generates on containers, and type-identifies any item put into it.

FIQHack

jonadab

You can light a greased sword on fire. Attacks with it will deal fire damage for a few turns until it burns out.

jonadab

Bishop monster, who moves diagonally very fast.

neonKow

If you press Escape while being grabbed by a monster, at a time when you could normally enter input (so not in the middle of messages), you get the message that says "You cannot escape from the <monster>!"

ChrisE

Escape as its own key should be used as an actual escape command, so you can do things like try to get out of pits and engulfers with it.

ais523

Random engraving: "This ASCII tile was donated by <user>.", where user is either a name of someone that has contributed to nethack in real life, or just pulled from the high score list.

vnroguelike, bhaak

Scale monsters' hit dice bonuses based on their size. In order to reduce the high amount of variance monster HP currently has, monster HP is now computed by this formula: (HD)d4 + HD*2*(size), where size is 0 for MZ_TINY, 1 for MZ_SMALL, and so on.

aosdict, Chris_ANG, FIQ, jonadab

You have access to the full total allotment of skill points from the beginning of the game (effectively making it so that gaining more levels isn't required to unlock skill slots). To compensate, you can only train skills by fighting at-difficulty monsters or higher, so you can't train everything by farming weak monsters.

aosdict, jonadab

The game makes fully clear to the player, in-game, how the skill system works and what the consequences of investing points in a skill means.

jonadab

Merge the damage versus small and damage versus large stats of weapons, since they don't really matter that much and add mostly pointless complexity. Damage should be more dependent on skill than on the size of the target monster. The only problem is how to stop the highest-damage weapons from becoming used by everyone because they're so optimal; perhaps skill should do something drastic like add an extra die with every skill level, allowing you to have weapons that are decent at low skill (by having multiple small base dice) but poorer at high skill (because adding more small dice doesn't work as well).

Chris_ANG, aosdict, jonadab

Make potions of oil more common, so that the player has more area-of-effect combat options (for throwing firebomb potions of oil). Possibly allow hardware stores to stock them.

jonadab

Gnomes spawned with a sufficiently high starting level, or else just a fixed percentage of gnome lords and a different fixed percentage of gnome kings, generate with a touchstone.

Chris_ANG, aosdict, jonadab

Long worms should be much faster than they currently are, and they get a damage bonus for each tail segment that is lined up behind their head.

Chris_ANG

An artifact boomerang which is a guaranteed first sacrifice gift for Archeologists.

deadnoob

New artifact spellbook Akashic Records:
Read for enlightenment
Can be applied like a stethoscope to probe adjacent enemies, doesn't cost a turn
When carried, gives extrinsic monster detection. Farlooking reveals enemy HP.
Invoke for precognition: for the next 100 turns, your attacks never miss, and enemies roll twice against you and use the lower result.
If you would be killed from HP damage from an attack during precognition, you will dodge the killing blow and all subsequent attacks on that round. Immediately ends the effect.
Might mesh well with the other encyclopedia idea, using it as a base item type.

Luxidream

Scroll of healeportation: performs both a heal and a teleport at once.

AmyBSOD

Vampires can't step onto sinks, because they "can't cross running water".

aosdict, deadnoob

Invoking Mjollnir allows you to cast a bolt of lightning as if from a lightning wand.

Vuks

Augment the stealth system by adding a monster AI attribute representing "hasn't sensed you yet, or has lost sense of you". Also allow players to take a deliberate action to conceal themselves. This would allow for players to hide in (or flee into) a corner or closet and allow a monster to pass them by, then get the jump on them afterward (perhaps in the form of a bonus for attacking an unsuspecting monster). Some monsters should ideally be able to conceal themselves as well, perhaps even by casting illusions that make a door appear as a wall or something to the hero, until discovered.

jonadab, aosdict

You can put rocks into a sack, oilskin sack, or bag of holding and then wield it and swing it at enemies. (This uses flail skill.) Damage depends on the total weight of the rocks.

elenmirie, jonadab

Clerical spell that gives you a certain duration of a property that steals enemies' maxHP and heals you when you hit things in melee.

jonadab

In variants where object materials is implemented: carrying gold items openly causes leprechauns, dragons, and Croesus to be automatically aggravated.

K2, hothraxxa

Undead can't step onto sinks, because they "can't cross running water".

deadnoob, aosdict

In variants with felt markers, allow them to write spellbooks and scrolls of mail - the other scrolls are the only thing they can't write.

jonadab, aosdict

The hero can either not write unknown scrolls and spellbooks at all (writing by appearance is still fine as long as the appearance is known), or else the chance of writing one increases with every scroll and spellbook the hero identifies.

aosdict, jonadab

Leprechauns (or anything with AD_SGLD) should steal items made of gold out of the hero's inventory.

K2

The Candelabrum refuses to light if it has fewer than 7 candles.

StatueSurfer, aosdict

Add a summoned bitfield to struct monst. Should be a bitfield rather than a flag so that it can track different details of how it was summoned (from trap/wand/etc, by player or by something else). Summoned monsters can have various anti-farming nerfs applied to them: no training skills, no corpses, no deathdrops, no starting inventory, no experience, etc.

Crawldragon, AmyBSOD

Unicorn corpses are never tainted from age, though they do eventually rot away.

rikersan

The chance of failing to polymorph into a target monster (whether chosen randomly or intentionally) depends on the base level of that polyform relative to your own level.

jonadab

Kicking a sink may produce an air elemental.

nyingen

You can trigger land mines from a safe distance by hitting the square with a polearm.

stenno

When a gremlin steals an intrinsic from you, you can recover the intrinsic by killing it or eating its corpse.

FIQHack

aosdict

If you have teleport control, quantum mechanics' attacks toggle your speed instead of giving you a free controlled teleport.

Deuce-Zen

Merge the rings of sustain ability and slow digestion into a "ring of stasis". Double-edged effects: slows down digestion like normal, but also slows down healing, energy regeneration, timer effects like confusion and sickness, any timing-out intrinsics, prevents exercise from happening, blocks or reduces to 1 effects that directly change attributes.

aosdict, rikersan

In variants with object materials: replace the shield of reflection with a "polished shield", which is nonmagical. It can come in any material, but only brass, copper, silver, and gold are shiny enough to make it also confer reflection. (That is, you can have a polished wooden shield or a polished iron shield, but the material just isn't lustrous enough.)

aosdict, rikersan

Hands holding a quarterstaff or wands don't count as being occupied for the purposes of calculating spellcasting penalty. (Perhaps generalize wands to any other non-weapon.)

Chris_ANG

Player monsters can randomly be named Dudley. If Dudley ever comes across a scroll of genocide, he will immediately genocide newts.

FIQHack

aosdict

When zapping a wand of wishing at Unskilled, you get a random wish.

FIQHack

AmyBSOD

Magicbane should block random item cursing from a fountain.

rikersan

Metal wands and rings never explode due to shock damage, as does the ring of shock resistance regardless of its material.

aosdict, jonadab

Shop type "psychedelicatessen": contains some normal delicatessen food, but also hallucinogens and lots of drugs.

Slash'EM Extended

aosdict

Disenchanters can eat magical items for food. (Goes for pets and players polymorphed into them. Not specified whether this should give the player intrinsics.)

rikersan

Tile that indicates, somehow, that it is suspicious-looking - it might conceal a secret door or something else discoverable, or it might be nothing, but it's a clearer hint to the player than usual. This would work well in a tiles windowport, but it's not clear how it could be done in ASCII.

FIQ

Instead of a mslow flag in the monst struct, use a signed char called "speedbon" which represents the amount of speed offset that the monster should have from its normal speed. This allows for more nuanced speed mechanics, like zapping a wand of speed monster or slow monster multiple times and having the effects stack.

aosdict, FIQ

Random earthquakes. Same effects as drums of earthquake, except not triggered by anything and not necessarily centered on the hero or anything special. Earthquakes (from any source) now can collapse diggable walls (turning them into floor spaces without pits) and drop rocks and boulders out of the ceiling. No effect in any Plane except Earth. Possibly, to limit this, a finite number of earthquakes can happen on any given level (after which it either collapses entirely, or just fails to produce more free rocks and boulders.)

aosdict, Pawkisinov

Healing potions don't give you different HP maximum increases depending on their beatitude any more. Instead, if they would have taken you above your maximum, your HP maximum is increased by that amount, to a maximum of +1 (healing) / +2 (extra healing) / +4 (full healing).

aosdict, rikersan

Non-intrusive ways to tell new players important parts of the game, like how to use #enhance. For instance, "You feel more confident in your skills. (Use #enhance to advance this skill.)"

aosdict, scorchgeek, zwihander

Cannibalism angers your god instead of removing telepathy.

aosdict, scorchgeek

Special message for a M1_CONCEAL pet reluctantly hiding under a cursed item.

jonadab

New conduct for not hitting things with thrown items, and another conduct for not casting offensive spells.

aosdict, eraserhead

#offering the Amulet on the high altar now breaks atheist conduct. To circumvent this, you can give the Amulet to an intelligent coaligned pet and stand adjacent to it as it offers the Amulet.

Wooble

Having both the hunger and slow digestion properties turns off all hunger-related messages and prevents hunger status from being displayed.

Deuce-Zen

The hunger property, instead of doubling hunger rate, halves any nutrition you get from any source, making it marginally more useful for eating large corpses.

aosdict, zid, scorchgeek

Sell price depends on Charisma, whereas buy price does not. (Slightly more flavorful.)

aosdict, eraserhead

Wearing an opera cloak allows you to sing like a musical instrument (e.g. the passtune).

eraserhead

Portals on the Planes come pre-mapped, so you don't need to bring 4 scrolls of gold detection.

scorchgeek

Give a Luck penalty for destroying a Sokoban boulder by polymorph shudder.

AmyBSOD

There is some sort of ritual you can do to store a soul (ghost, or monster's or pet's soul from its corpse before it rots) in an item, and later release it into a freshly killed corpse to make the soul inhabit that body.

aosdict, Chris_ANG

Torches, which can be created by dipping a club into a potion of oil. Torches are their own item, not just a "lit club" (though possibly the lamplit flag could be used for this), and have a light radius of 3. Deals additional fire damage to monsters it hits, but may go out. May light the hero on fire if they fall down the stairs with a lit torch in inventory.

Chris_ANG, aosdict

If you consort with a foocubus while Lawful, "You feel unclean."

aosdict, FIQ

Add a "fruit" database entry: "They say this is edible. Some adventurers have strange tastes." and tweak the database code to recognize a typed-in fruit name in the game as this entry.

jonadab

Some weapons' unidentified appearances are shared with other weapons, so characters who start the game without knowledge of many weapons have to play a bit of an ID game with them. For instance, scimitar and katana could just be changed to "curved sword". This has problems, though: it doesn't translate very well to tiles, and it's vulnerable to weight-ID if two weapons with different weights share the same description.

jonadab

Ring of carrying: new chargeable ring that multiplies the weight of the player's inventory by (1 - (0.05 * enchantment)) when worn. Stacks with a second ring. Initial charge and beatitude is set the same as any other charged ring.

jonadab, riker, aosdict, greqrg, kritixilithos, FIQ, AmyBSOD

Change rne() so that it doesn't depend on the player's experience level: instead it depends on the current level depth. Specifically, change its theoretical maximum from max(XL/3, 5) to max(depth/5, 5).

aosdict, greqrg

Meleeing monsters while you are afflicted with a zombification disease will start zombifying them.

FIQHack

jonadab

Smoke cloud monster (v): has a mild fire damage attack and a suffocating smoke attack. Generates in fiery areas.

riker, aosdict

Add a "magivore" monster flag, or else hardcode this for disenchanters: they can feed on magical items like incantifiers do (though without the Pw gain, just for nutrition).

riker

Ring of fast living: gives an experience multiplier and increases hunger rate drastically, multiplies your damage but also multiplies damage you take.

zid, ChrisE

Sokoban will either contain a prize of three amulets (one reflection, one versus poison, one other), or three bags (one holding, one oilskin, one other).

jonadab

Frost lamp, a tool which gives out a radius 3 cold aura. Water and lava within the radius freeze and then revert once out of the radius. Fiery monsters take damage from being in the radius. Eventually runs out and has to be recharged.

riker, Demo, aosdict

Condensing all of NetHack's poison mechanics into one unified mechanic:
Dexterity and Constitution poisons are removed. Quasits (the only AD_DRDX attack) might still directly harm Dex, but it's no longer flavored as poison. Rabid rats (the only AD_DRCO attack) don't cause poison, they cause disease, which hits Constitution. Poison will now only affect Strength.
Poison is now implemented as a timing-out trinsic. The amount of Str loss is a direct function of how much timeout is left, so Str will gradually recover as the poison goes away.
Passing Con saving throws could give small bonuses to decreasing the timeout faster than normal.
While poisoned, HP regeneration is either impeded or stopped entirely, or else the player's HP is damaged every turn, or every several turns.
It could also heavily abuse Str while it lasted instead of being directly tied to Str.

jonadab, aosdict, greqrg

Frost Brand is made of platinum and deals triple damage to monsters that are fire resistant but NOT cold resistant. Fire Brand is made of gold and deals triple damage to monsters that are cold resistant but NOT fire resistant.

NeroOneTrueKing

TDTTOE: Skeletons use gendered pronouns if and only if the player is an Archeologist (and therefore used to analyzing bones).

aosdict, Chris_ANG

Small spellbooks. Take extra time to read if the player's size is not MZ_SMALL or smaller. Any spellbooks a gnomish character starts with and any spellbooks generated in Minetown shops are small. A spellbook generated otherwise has some fixed chance to be generated small.

NeroOneTrueKing

Gnomish characters read spellbooks faster than other races.

NeroOneTrueKing

Nurse healing should cure other ailments like sliming and possibly stoning.

AmyBSOD

All sinks spawn with a ring buried beneath them. If you kick the sink and get the "Flupp! Muddy water" message, the sink will spit out one of the rings buried under it. This removes the need for the S_LRING flag, and also allows players a non-destructive way to retrieve rings they dropped down the sink.

jonadab

Kicking a sink can also dislodge a small swarm of sewer rats, or snakes. Unlike puddings which are one per sink, these don't stop coming until they're extinct.

jonadab

Add a defence/evasion skill, which is practiced by having monsters miss the player (while not wearing torso armor?) and grants an AC bonus when enhanced.

kritixilithos

Jumping outside the jumping range ("Too far!") should not cost a turn, and the interface should make the jumping range clear, perhaps by highlighting all the squares you can jump to. Or else if you try to jump to some square outside the jumping range, you'll jump as far as possible in that direction within the jumping range.

aosdict, kritixilithos

#stomp command that lets you stomp on a grounded creature that is X sizes smaller than you. A hit will instakill it.

kritixilithos

Merge the rings of slow digestion and hunger into a single chargeable ring of digestion. Negative values increase hunger faster, positive values slow it down. Duplicating the effect of a vanilla ring of slow digestion would require getting a +10 ring or stacking up to 10 with two rings. (Possibly the negative/positive values should be switched, but that would complicate the generation code.)

jonadab

Artifact whose invoke power creates attack wands.

ais523

Track "did not enhance any skills" as a conduct.

jonadab

Iron chains are given either whip or flail skill.

aosdict, Chris_ANG, ais523

Skeletons, or any other monster with MS_BONES, don't paralyze you by rattling their bones if you're hallucinating; instead you get a message about it playing the xylophone.

aosdict, Webmant

Provide an option to label branches with the branch name instead of using "Dlvl:" all the time. Also allow it to be shortened to "DL", with no colon, for those who want extra space in the status bar.

JarrodB, jonadab, aosdict

Raise the XL threshold of dipping Excalibur for non-Knight roles to around 9-12. Knights can still dip at level 5.

aosdict, riker

Engraving does not make you helpless. Instead, it should be an occupation.

aosdict, FIQ, vevais

Attacking in melee with an unsuitable weapon like a launcher should negate the player's Str bonus or monster's weapon attack bonus.

aosdict, xyzyxx

Holy water fountains in temples (would require balancing though).

ChrisE

Use timing-out intrinsics to invert the hunger clock: use the limit on how fast you can hunger as a restriction on how many intrinsics you are keeping up.

jonadab

Make identify scrolls generate blessed more often (perhaps 1/3 of them blessed, 1/3 uncursed and 1/3 cursed, or 1/2 1/3 1/6, or something) to remove the incentive for players to hoard everything until they can get holy water.

jonadab

Make blessed identify give no more type-identification than uncursed identify, but it will identify the beatitude and spe of all its items. Uncursed identify will identify the beatitude and spe of some, but not all, items.

Chris_ANG

Gold objects deal extra blessed damage and extra cursed damage (i.e. extra damage from wielding a blessed weapon versus undead will be enhanced if the weapon is gold).

Chris_ANG

Barracks chests should contain gold, the soldiers' payroll.

Chris_ANG

Spiked pits and a lower percentage of pits generate with an item or two buried. When you fall into one, any buried items are automatically exposed. The most commonly generated items here are a few gold or an eroded weapon.

Chris_ANG

Cancelling a unicorn horn makes it non-magical and removes its curative properties.

jonadab

Reduce the odds that a nonmagical potion polypiles into a magical potion, to disincentivize mass-blanking potions and polypiling them.

aosdict, riker

Covetous monsters can warp to the up stairs only if they know where the up stairs are. Demon lords would know this in their own lairs, but not otherwise, and monsters randomly spawned on a level may or may not.

jonadab

If you have divine protection and become near death from a timed instadeath or low HP, some or all of your protection may automatically convert itself into a cure: "You suddenly feel the power of [deity] surround you! You feel limber/cured/much better/etc." This should probably work for a narrow range of symptoms (probably not HP loss, possibly any major trouble).

riker

Make death messages more diverse and flavorful. Base it on the attack type of the monster and possibly the weapon used, so that "killed by a jackal" becomes "clawed/mauled/shredded by a jackal", "killed by a gnome" becomes "bludgeoned to death by a gnome" if it was wielding an aklys, "stabbed to death by a gnome" if it was wielding a dagger, etc.

nyingen, ais523

Wraith corpses cannot give food poisoning, though they can still rot away.

mtf

Intrinsic see invisible now works only at a range of 2-3 squares. Extrinsic see invisible works at the current see invisible range (unlimited as long as you can see the space normally).

NeroOneTrueKing, Chris_ANG

Turn trying to open a door into an occupation: if you get attacked or otherwise distracted while trying to open the door, you will stop, but you don't have to constantly keep trying and failing to open it.

jonadab

Dogs will eat candy bars off the floor, but will then get sick or nauseous from eating it.

aosdict, jonadab, FIQ

When you have displacement, you displace your pets appropriately even when stunned, confused, or hallucinating.

AmyBSOD, jonadab

Intentionally destroying an artifact reduces the artifacts generated counter, so you can wish up new ones.

CursedFlames

Change the "killed by the wrath of <god>" death to "annihilated".

nyingen

A Gehennom Gnome Fortress, like a demon lair except with gnomes. The gnomes are physically weak but have strong crossbow attacks (and clockwork minions).

Tarmunora, riker

Status effect that temporarily lowers all attributes to 3.

Demo

Implement farming, in certain special rooms called greenhouses. Allows you to grow fruits, carrots, garlic, trees, etc.

kritixilithos

The monster spawn rate gradually decreases the longer you spend on a level. (May not apply if you have the demigod flag set or are carrying the Amulet.)

AmyBSOD, aosdict

Statues can come in bronze or other types of material (perhaps with the addition of object materials).

bhaak

Long worms and pythons can be saddled and ridden as steeds, but only if you are a small monster.

jonadab

Remove the extra healing, cure blindness, and cure sickness books. The healing spell scales with skill level. At skilled it also cures blindness, and at expert it cures both blindness and sickness.

riker

Gelatinous cubes specifically seek out scrolls labeled YUM YUM to eat.

rumflump

Warn the player before they melee a monster with passive attacks.

bug_sniper

You can make deals with demon lords (or maybe just one demon lord) for special abilities, but this has major drawbacks.

FIQ

Debilitating wound system that expands on wounded legs. Includes wounded arms and various types of disease and poison, all of which provide various debuffs. Quaffing any healing potion cures all of these at once on top of its usual HP healing.

Chris_ANG

Add restrictions on levelporting for various roles to help differentiate them.

Chris_ANG

Rogues can build and set traps, more types of traps than just plain pits and land mines and bear traps. Traps may consume some types of items to be set, like a sleeping gas trap will consume potions of sleeping. This should probably not be totally reversible through #untrapping. Intended so the player can pick their battles and set up traps in an advantageous position.

K2, stenno

Add two fields to struct trap: an object, which represents the "ammo" of the trap (darts, arrows, potions of oil), and a number to represent the "level" of the trap (which can affect a lot of things, such as a to-hit bonus the trap gets, how hard it is to untrap, or what the skill was of the player when they set the trap).

Chris_ANG, aosdict

For TDTTOE, writing "Elbereth" in the prompt for writing a scroll should translate to "scare monster".

dizzylizzy, aosdict

Merge crossbow and bow skills so that gnomish rangers don't get hurt by the lack of ammunition.

neonKow

Type of arrow that is made out of enchanted worm teeth. Gives the racial arrow bonus to anyone using it.

CctheOwl

Dipping eucalyptus leaves in water gives you a potion of tea.

neonKow

Hallucination should prevent against all death magic, including death rays. Not just the touch of death.

Muad, aosdict

You can cast spells from HP when you have insufficient Pw. Each point of HP is worth 2 points of effective Pw. Doing this a lot or in large quantities may drain your HP max.

mtf, aosdict

More angelic maledictions:
"Weep, for [your god] has abandoned you!"
"Your unholy soul shall be [cleansed/purged]!" (cleansed if coaligned, purged otherwise)
"[Tremble/Cower], mortal!"
"Kneel, or thou shalt be knelt."
"Bow before me!"
"You viper!"
"Repent, sinner!"

Chris_ANG, aosdict

Move angelic and demonic maledictions out of quest.txt; they have nothing to do with the quest. They should probably still live somewhere in the dat folder.

jonadab, Chris_ANG, aosdict

Blessed figurines always make the monster turn out tame. Uncursed ones make a tame monster 80% of the time and peaceful 20% of the time. Cursed ones make a tame monster 20% of the time and a hostile monster 80% of the time.

Chris_ANG

Figurine monsters generate with an inflated monster generation difficulty.

aosdict, Chris_ANG

Shimmering dragon scale mail grants see invisible.

NeroOneTrueKing

Blessed scrolls of identify, if the player selects a container, will bring up a second menu that allows items in the container to be identified.

jonadab

The confused scroll of identify, if non-cursed, identifies a random unknown object class and adds it to your discoveries list, even if you've never seen any of that object.

aosdict, ais523, jonadab, FIQ

Elves and possibly Rangers get an alignment penalty for cutting down trees. Dwarves get an alignment bonus.

aosdict, jonadab

Make fireballs like old-school D&amp;D: the explosion isn't a certain radius; instead it has a defined volume, and will expand out from its origin point via random breadth-first search. This makes it dangerous to use in confined areas.

ais523

Temporary hit points and Pw: your maximum goes above its normal bounds for some time, before returning to normal. If your normal maximum changes for some reason, the temporary maximum changes by the same amount. There are two proposals for how the effect should end:
The entire effect is timed, and once it ends the temporary buffer vanishes. If your HP would go below 1 as a result of this, you could either die or have it set to 1.
The temporary buffer drains away at the rate of 1 point per turn, and the effect naturally ends once it's gone.

aosdict, Pavel

Spell that grants temporary hit points.

Pavel

Lure, which attracts monsters to you. Could be a magical non-consumable item, or a charged item that amounts to spraying yourself with scents. The Amulet of Yendor should also have this effect, at its maximum level at all times.

Pavel, aosdict

Scroll that tells you the dungeon overview for the next 5 levels of the dungeon. If blessed, shows more levels; if cursed, shows fewer levels or omits details.

Pavel

Dungeon branch or level filled with toxic contact gas (breathless doesn't help, or only helps a little) so that you constantly take damage and must bring a lot of healing with you. The deeper you go, the worse the gas becomes, but the loot gets better.

Pavel

Incorporeal monsters should be immune to mind flaying (and probably most physical) attacks.

Mandevil

Casting a forgotten spell to confuse yourself consumes some Pw, perhaps one point per spell level, or just a random amount.

jonadab, K2

Additional temporary effects accompany drinking a potion of booze. The effects wear off when the confusion does (so if you extend it by, say, drinking a potion of confusion, the effects are prolonged). There is consensus that there should be both positive and negative effects; all of the following have been proposed:
A damage bonus, or even double damage
Temporary HP
An accuracy penalty.
If you're a dwarf, the effects get magnified
If there is any such thing as a player-is-scared effect, it is canceled when you drink the booze and blocked while you're under the influence.
Any AC from your armor is nullified

K2, aosdict, jonadab

Engraving successive digits of pi on squares in a line gives you a cream pie for each new square.

kritixilithos

Ring or amulet that causes your spellcasting to draw on HP instead of Pw. Each point of HP is worth 2 Pw points. If cursed, doubles spell Pw costs. If blessed, energy regeneration will regenerate HP until full before regenerating Pw.

Pavel, elenmirie

Scroll that restores you to full health but decreases your maximum health.

Pavel

If you can make deals with demon lords: one such deal is to boost a stat of your choice in exchange for permanent reductions in other random stats.

Pavel

Make the amount of bonus movement points from temporary speed directly dependent on its remaining duration. Also provide diminishing returns where giving yourself more speed boosts on top of already having temporary speed gives you less extra duration than it otherwise would, until eventually you can't get any more duration than 1 per turn. These bonus movement points should also stack directly with all other speed sources, and be visible to the user in the status bar.

jonadab, aosdict

Elves can engrave Elbereth and use it on the player, scaring them.

FIQ

When the player is afraid of a monster, to-hit is reduced and they may not be able to attack that specific monster at all.

FIQ, Elronnd, aosdict, jonadab

The Orb of Detection can detect the presence (but not location) of artifacts on the level. Possibly this is an Archeologist-only power.

FIQ

A wand that, when it hits a creature, saves that creature's position and forces it to teleport back to that position after a few turns.

Pavel

Ensure that roles that start with spellbooks always have enough Pw for one castable spell.

raisse

Deployable barricade on a tile. Blocks movement; must be attacked or kicked several times to be destroyed. Presumably lightweight to actually carry around.

Pavel

Very rarely, when eaten, candy bars have a Golden Ticket inside, which does something good like grant a wish. (Requires some method of not being farmable; possibly, polypiled candy bars have obroken set, and obroken candy bars never have a ticket in them.)

Chris_ANG, aosdict, jonadab

Reduce the impact of a single master mind flayer attack, so that they don't just spawn out of nowhere (e.g. via harassment) and one- or two-hit kill a character with low Intelligence.

FIQ

Wizard-harassment summon nasties should produce a "Monsters appear from nowhere!" message, and this message should force a --More--.

jonadab, FIQ, AmyBSOD

If the hero's HP would be reduced below 1, set it to 1 instead (dependent on Luck? Or Dexterity?).

bhaak, FIQ

Chatting to trolls while hallucinating makes them appear to say troll-bait sentences.

FIQ

If you polymorph, and are not helpless, all of your torso armor that has a delay of 1 or less and isn't stuck under slower armor is automatically removed. This includes all cloaks and shirts.

aosdict, Wooble

More harassment effects: the chance of respawning the Wizard is a fixed 1/7 and the rest of the effects are equal probability. Multiple non-duplicate effects may happen at the same time.
Unchanged: curse items, summon nasties, vaguely nervous, aggravate monsters
Darken much of the level, and extinguish or destroy light sources.
Drop boulders around the upstairs, or iron bars.
Make the Amulet and any fake Amulets much heavier until the next intervention.
Spawn pools centered on the player, with sea monsters in them.
Spawn lava around the level, not under the player.
Create a hole or pit under the player.
Create a stinking cloud centered on the player.

ozy

Change the message "This food tastes okay." for "palatable" food to "This food tastes gamey."

nyingen, zid

Slaughterhouses as a Gehennom special room, filled with corpses, leashes, and knives.

nyingen

A race where you start polyinited to a low level monster and with every level you gain, you can polymorph into a stronger monster.

nyingen

-, interactable by farlooking them while adjacent). Might be able to be haunted - can produce a ghost?

Chris_ANG, aosdict

Mind flayers have to grapple your head before they can successfully suck your brain, forcing them to spend a turn doing this. If you have a greased helm, this gives you at least one extra turn to act since they will not be able to grapple your head until the grease dissolves.

Chris_ANG

Swap the spell levels of sleep and cause fear: sleep is now level 3, cause fear level 1 (to maintain there being a level 1 enchantment spell).

K2, aosdict, FIQ

Potion throwing is a skill, and #enhancing it will let you get stronger effects out of thrown potions. Later game monsters may throw potions with this skill enhanced. If traps throw potions, they always do so at Unskilled.

jonadab

Leprechauns are occasionally generated with a sack of gold rather than gold pieces in free inventory.

jonadab

Overhaul poison so that its effects are less random: some might still cause instadeath, but it would only be found in the late game or via bosses like Demogorgon and Scorpius; early game poison shouldn't drain multiple stat points at once.

aosdict, raisse

Engulfing by a water elemental or a monster with a digestion attack cleans off any creampie blinding the hero has.

jonadab

All H can step out of a pit in 1 turn.

FIQ, raisse

You can set some fixed inventory letters in the rc file, so you don't have to adjust them manually. In its simplest form, this would apply only to starting inventory, and would allow things like a Tourist's credit card to be guaranteed to be placed on a familiar letter.

raisse

Sensitive eyes attribute or status: you can see farther in the dark, but anything that creates light such as the scroll or a camera will blind you.

Pavel

Nymphs are weak spellcasters and may generate with a few enchantment spells or have hardcoded ones like sleep and charm monster.

FIQHack

aosdict

If you don't have a default window port set in your options file or the sysconf, you get to choose which to use on startup.

FIQ

The higher your skill is with your wielded weapon, the lower the chance is that an enemy will yank it out of your hand with a bullwhip.

jonadab

One or two softball easy player monsters that generate early in the dungeon, with mostly starting gear, and are not hard to kill.

FIQHack

aosdict

When "Sting cuts through a web!", the web is destroyed. Currently it only allows you to escape the web in 1 turn and does not destroy it.

aosdict, AmyBSOD

If a pet moves over a square with multiple cursed items, it moves "very reluctantly".

riker

All Banes artifacts are bloodthirsty versus their respective monster type.

riker

Grand Master martial arts skill allows you to (attempt to) force-fight boulders and statues to shatter them with your bare hands.

K2

Make Big Stick (Cav quest artifact in Fourk) deal two bonus attacks which may or may not hit (but it still all appears to be one hit). If both bonus attacks hit, the target is stunned and confused.

riker

Clubs may stun monsters that they hit. Perhaps the chance increases with skill, such as 0% unskilled, 10% basic, 20% skilled, 40% expert.

FIQ, mtf

New role "Deprived": starts with a poor club and shield; no other items.

Winsalot

Non-magical tools that can be used to heal wounds.

AmyBSOD

The maximum difficulty a monster can be generated at is independent of player experience level. Only the level difficulty (and perhaps other player-independent stats) matter. The details of how the curve of monster difficulty compared to level difficulty should look are up to debate; NetHack4's is a piecewise function that climbs slowly until level 10 and thereafter is (level difficulty - 5).

aosdict, FIQ

You can convince peaceful intelligent monsters to join your cause (taming them) via #chat. The outcome depends on several factors: yours and the monster's alignment (lawfuls have a very hard time recruiting chaotic monsters), yours and the monster's level, your Charisma, and possibly others. Failing might turn the monster hostile, or do nothing (but you can't try again). More complex behavior could possibly be implemented with the monster demanding something from you or making you do something. Also, give bonuses if the monster you are trying to convince is of your own race.

FIQ, aosdict

Various ideas to prevent powerful bones generated on a level's upstairs from instakilling a player:
Don't generate bones if the player died on the upstairs.
Going downstairs doesn't use a turn, but going up does.
When saving the bones, set all monsters' movement points to 0.
If the player died on the upstairs, swap the upstairs and downstairs locations.
A way to "peek" up or down the stairs without going there.

mtf, FIQ, aosdict, Chris_ANG, ahrimen

If you take damage from eating a hot corpse while hallucinating, you get a YAFM about spicy food.

dNetHack

aosdict

Monks will only get gifted weapons whose skill they have previously trained at some point.

riker

Healers get Basic skill in divination spells.

NCommander

Healers start with higher Intelligence (perhaps at the cost of their high starting Charisma, which they don't need as much). Priests could stand to have guaranteed a bit more Int and monks a bit more Wisdom, as well.

hothraxxa, elenmirie

There are some rare non-farmable ways to exercise Intelligence. Learning a new spell, getting a major Oracle consultation for the first time, probably more stolen from the many ways to exercise Wisdom.

aosdict, hothraxxa

Scroll of knowledge: rare scroll that directly increases Intelligence when read.

hothraxxa

Trolls give two YAFMs when chatted to: "Problem?" normally and "Trolololol!" when hallucinating.

Homage

You can wield artifacts in your offhand, but they must be non-intelligent, non-gifted, and non-crossaligned. (Non-wished-for is an option, but may be too exclusive.)

dizzylizzy, aosdict, Wooble

Assuming the Wands Balance Patch: higher wand skill makes wand rays harder to dodge.

jonadab

Most corpses have sharply decreased amounts of nutrition (from the current values).

aosdict, Chris_ANG

Tins give min(regular tin nutrition constant, corpse nutrition) nutrition when homemade, to fix things like killer bee corpses granting 5 nutrition but going up to 50 when tinned.

Chris_ANG, Demo, aosdict

Polymorph beams stop at the first square on which there's an object or a monster they affect. In addition, golem formation is made much more aggressive and item-destructive to discourage one-large-stack polypiling.

Chris_ANG, aosdict

Specify the amount of wand charges a wand should generate with per wand. Polymorph wands should get fewer charges than other beam wands, for instance.

Chris_ANG

Convert the spellbook of polymorph to a form that polymorphs only monsters and never items.

Chris_ANG

In order for a random item to drop as a death drop, it must be able to have been carried by the monster. This means that newts and such won't get many death drops and the ones they do will be small.

Chris_ANG, aosdict

Special level or branch that is populated by dinosaurs and an intelligent reptilian humanoid called sleestaks. There is an artifact somewhere in here that is guarded by the dinosaurs and sleestaks.

K2

Fix race base monster weights: human weights should be dropped from 1450 to 1000, elves should be dropped to 500, dwarves should weigh a bit more than elves, orcs should be between dwarves and humans, gnomes should be lightest.

FIQ, jonadab, aosdict

Blind or eyeless monsters aren't affected by invisibility or displacement.

FIQ

Randomized appearances for each type of egg.

oh6, trwyth

Manes and lemures should count as undead rather than demons, and should perhaps be moved to the ghost or wraith monster class.

jonadab

Helms of opposite alignment use a hash function for determining what alignment they'll set a neutral to, instead of just using object ID mod 2.

FIQ, aosdict

Float stone, a gray stone which has negative weight. Non-stacking, and rare. If you get enough float stones to more than cancel out your own weight and the weight of any possessions you're carrying, you levitate. Possibly doesn't work when put into containers. May gain positive weight when cursed, or greater negative weight when blessed.

FIQ, jonadab, ais523, aosdict

Monster hallucination, if implemented as a status, should be rather stronger than confusion: when confused, monsters can still see what the other monsters around them are, but when hallucinating they ought to see the same random monsters as the player does, and lash out at any of them.

aosdict, FIQ, jonadab

Polymorph, teleport and levelport traps should disappear once used by any monster (including the player). Or else they have a low-ish chance of disappearing per each use.

raisse, aosdict, FIQ, AmyBSOD

The scroll of create monster now summons only 1 monster (occasionally 2 or 3). The beatitude determines whether they will turn out allied with the reader (blessed), created normally with the usual probabilities of being peaceful (uncursed), or whether they will be hostile to the reader or omnicidal (cursed).

aosdict, FIQ

Better ghost scaling in general. Ghosts should have a wide range of strength levels, and should be capable of posing problems even to late game characters. The more ghosts you summon by repeatedly entering a haunted temple, the stronger they get.

AmyBSOD, aosdict

A "reset button" for Sokoban, which restores all the original holes and resets all the original boulders, and places the player on the downstairs. Probably not activatable after the level is solved. Flavored as some sort of mechanism.

ais523, jonadab

Enchantments on armor and weapons time out (rather slowly). Also, any erosion damage to a positively enchanted item will be absorbed by that positive enchantment, which then vanishes in proportion to the amount of erosion. Perhaps the enchant scrolls should be made more common or cost less ink to balance this.

ais523

Remove the spellbook of haste self so that casters don't have a large advantage in speed over non-casters.

FIQ

Haste self or other extrinsic speed sources hurt your AC and/or to-hit.

jonadab

Merge extra healing, cure sickness and cure blindness, and make the resulting spell level 6. Or just merge cure sickness with cure blindness.

rikersan

Vapors from the potion of polymorph should cause a brief or minor polymorph. Possibly the "you feel like a new foo" effect.

FIQ, aosdict

Player monsters, rather than just being randomly hostile, actually try to quest for the Amulet, and they do this even when you're not on the same level. If you wait on the Dlvl1 upstairs for long enough, player monsters will enter and quest downwards, and eventually one will come back up having retrieved the Amulet. If the player monster with the Amulet leaves the dungeon or reaches their own high altar without you, you lose.

FIQHack

AmyBSOD

Guarantee a random sack somewhere in all Minetown variants.

aosdict, hothraxxa

Anachrononaut divine interactions (alignment record changes, murder penalties, etc) are all recorded and saved by the game, but have no effect since they have no god. Once they save the future and their god is restored, all of these catch up to them at once.

dNetHack

aosdict, FIQ

Vegetarian pets will eat meat if they are starving, but they only get 10% of the regular nutrition from it.

AmyBSOD

Get rid of the enchant armor and enchant weapon scrolls. Artifacts have fixed enchantment values. Higher-enchanted gear spawns as depth increases.

Tarmunora

Give unicorn horns a to-hit penalty: they are not a manufactured weapon, and are not designed to be wielded in your hand.

jonadab

Healers can use an uncursed unicorn horn as if it's blessed. They could also get the unicorn applied passively every turn as long as it's wielded (with or without gloves on).

K2

The player's own ghosts generate peaceful.

FIQ

Dipping a ring of polymorph control into a potion of polymorph allows you to control the ring it turns into (not its enchantment though, if the ring is enchantable).

hothraxxa

Certain monsters (e.g. the Riders) shouldn't be scareable by getting a ghost from a bottle.

stenno, aosdict

Make most if not all rings chargeable:
Hunger / slow digestion: merge, and the positive and negative enchantment work different ways.
Stealth works in a radius / makes monsters have to roll higher to detect you.
Warning increases or decreases its regular radius.
Aggravate monster works in a radius, or affects monsters' rolls for being aggravated.
Invisibility / see invisible: work in a radius, possibly.
Searching: radius or have it affect your chance of finding something
Polymorph / teleportation: affect the frequency at which it triggers
Conflict: radius or affect monster rolls
Most other rings that confer binary trinsics like teleport control or free action or sustain ability are difficult to make chargeable.

jonadab, aosdict, greqrg

Vortices confuse you after you spend a few turns engulfed in them, because you're dizzy from spinning around so much.

aosdict, greqrg

You should be prompted to confirm before attacking a monster while standing on Elbereth.

FIQ

Having an Elbereth square fade under you in 3.6.1 makes the square permanently unengravable.

mtf

Peaceful priests and angels of your own god on Astral help you out by attacking hostiles. Possibly only if your alignment is good.

aosdict, FIQ

Conflict negates Elbereth protections.

FIQ

Have a value that tracks the next turn Luck will check its timeout. Once the timeout ticks, it will re-randomize this value to some other turn.

jonadab

Sinks' glyphs should be changed to {.

FIQ

When hallucinating, you hear monsters that can speak say funny things. Possibly only when #chatted to; they say "O great wise [bogusmon], how may I help us defend us all against wicked adventurers who quest for the sacred Amulet?"

jonadab

Make quasits generate in large groups.

jonadab

Wood golems drop small shields in addition to their quarterstaffs.

FIQ

Add some incentive for orc characters to prefer orcish shields over elven ones.

FIQ

Higher skill in a spell school allows you to subtract some points off its Pw cost.

jonadab

Setting fire to a web should burn through it, spreading to any adjacent webs and destroying all of them.

hothraxxa, aosdict

Casting wizard lock at Expert skill will transform a door into an iron door or create an iron door.

xNetHack

hothraxxa

One or two Orcish Town exits are blocked by boulders instead of iron bars. This allows the player to get inside when they're ready without requiring digging or acid, but won't allow the orcs to escape.

aosdict, FIQ

Monsters carrying food will eat it when at low health and get healed by it.

AmyBSOD

Pets don't go feral if you are both in Sokoban, even on different levels.

mcw

The Caveman pantheon should be changed to monosyllabic god names like the rest of the Caveman-specific text.

Fourk

aosdict

Change the Ranger quest artifact to an infinite quiver that can produce an endless supply of arrows, rocks, or crossbow bolts, preferring to match to whatever the hero's wielded weapon is. This benefits gnomes who want to use crossbows.

aosdict, K2

Dipping mundane tools into potions of gain energy charges them with the same beatitude as the scroll would. Possibly extend to magical tools and wands, but only allow the uncursed charging effect.

Novel, aosdict

Polymorphing into a big scary monster like a dragon or minotaur causes some monsters (failing a resistance roll?) to flee.

Wooble

You can convert spellbooks into scrolls. You may get scrolls related to the spellbook topic if possible, otherwise random. Possibly beatitude affects the number of scrolls produced.

mcw, Grasshopper, MiseryMyra

Different game ending messages than "You die...". Pull in some from other games: "WASTED", "YOU DIED", "FATALITY", "Game Over", "Your bones are scraped clean by the desolate wind, your Vault will now surely die", "Haha noob"

rikersan

Allow a count for eating, or else have the character stop once they hit Satiated.

bug_sniper, mcw

Wielding a light source increases its radius by 1. Or possibly 1 if offhanded and 2 if directly wielded.

mcw, aosdict

Sanctuary in coaligned temples is granted only if your prayer timeout is nonzero.

mcw

Watchmen will attack monsters that they see attacking you unprovoked.

bug_sniper

Potion of antivenom/antidote which cancels out any Str loss from poison. (Not really that useful if poison is simple Str loss; blessed restore ability is superior, but if poison is an actual status effect, it would be more useful.)

bug_sniper

Conflictless conduct: never have a monster attack another monster while influenced by conflict. Would be best if you can safely ring-test conflict, perhaps it gives some message like "You feel aggravation" or "You feel irate" when wearing it (these messages would be shared with the ring of aggravate monster so as not to be unambiguous).

aosdict, bug_sniper

Confused genocide doesn't kill you; instead it genocides something close to what you named, like the opposite case of a monster letter.

Zachaq

Worker ant that restores walls that have been dug out.

xyzyxx

Demigod level containing a boss which is generated from a real player who recently ascended.

Winsalot

Spell or potion that keeps your HP from dropping below 1 for a limited time.

Pavel

Vaudeville banana peel traps.

Grasshopper

Dirt terrain, behaves the same way as stone but digs faster.

Pavel

A way to allow the player out of locked shops they teleport into. Possibly #chatting to the shopkeeper, or trying and failing to open the locked door from inside the shop.

FIQ, aosdict

When fountains dry out, they become empty fountains instead of disappearing (possibly { symbol?). There is something you can do to restore the water to a dry fountain.

Pavel

Make the meat ring into a randomized ring appearance so that stone to flesh becomes more interesting.

bug_sniper

When you get arrested by the Watch or a guard, you are teleported to a prison level, from which you must escape.

stenno

Scroll which makes an evil clone of a target monster which will attempt to kill it.

FIQ

Attempting to wear armor while already wearing armor in that slot will prompt you to remove it.

bug_sniper

One of the playable races, possibly halfling, should get a permanent +1 to Luck similar to the full moon effects.

jonadab

Magical gear automatically adjusts its size to fit its wearer. (This could even be an object property.)

dNetHack

Grasshopper

Enlightenment tells you how many more turns you have for timing-out effects.

Pavel

Greased items that get exposed to fire become flaming for a certain number of turns afterwards (and then the grease is gone).

Wooble

Command that allows you to call your pets towards you.

deadnoob

Small room with a door near the start of each Sokoban level for you to place your pet in while you work.

Shishire

Wearing kicking boots protects you from all damage caused directly by you kicking things.

nervous

Healers heal monsters when meleeing with no wielded weapon or worn gloves, sort of like nurses.

dizzylizzy

Throwing things against walls or dropping certain metal objects produces some noise and wakes monsters.

nervous

Using a stethoscope on a monster requires that you succeed in making a to-hit roll against it. Otherwise, it doesn't work.

dizzylizzy

Am amulet versus thievery, which protects you from all theft attacks including nymphs, leprechauns, foocubi, and possibly even Amulet-stealing attacks.

ChrisE, aosdict

Lithivorous monsters can gain intrinsic speed by eating a dilithium crystal.

dizzylizzy

Using a cursed tonal instrument makes the gears and tumblers in the castle drawbridge lie to you.

Wooble

If a monster is hurtled into another monster (i.e. from a monk's staggering blow), both monsters wake up.

Novel

Mimics can pretend to die, mimicking a mimic corpse or appropriate death drop.

ChrisE

If you are wearing fencing gloves and are carrying some iron chains, you can create iron bars (a "fence").

Grasshopper

If you're polymorphed into a unicorn, you can #dip potions into your horn.

AmyBSOD

If you die from overeating and then are lifesaved, you automatically finish eating.

nooodle

Graffitist role, in which your job is to go around making graffiti everywhere.

SLASH'EM Extended

aosdict

Give some monsters the M2_SWIM ability: rats, possibly dogs, possibly horses.

jonadab, aosdict

Attacking with a crossaligned artifact weapon halves all damage you deal.

AmyBSOD

(Object materials dependent): You can write and instantly read a scroll onto a piece of paper armor (with a magic marker, incurring the regular ink cost).

K2

(Object materials dependent): Allow scrolls to generate as metal, flavoring metal scrolls as engraved plates. These cannot have their labels wiped and cannot have new labels written on them, but they are immune to fire and water damage.

Pavel

When a black pudding is created from a sink, rings buried beneath the sink may be placed into the inventory of the pudding.

bug_sniper

New monster "master grid bug". When they zap you, you get a status effect that forces you to move only orthogonally like a grid bug for some time.

Pavel

Drinking booze while already under its effects causes hallucination.

Pavel

Allow teleportation onto the vibrating square, since it isn't really a trap.

Mandevil

Item called "message in a bottle" that sometimes generates near water sources. You can read it to get a random rumor.

Pavel

Burnt offerings: via some mechanism, you get the corpse smoldering on the altar. When sacrificed, it is treated as higher difficulty.

dizzylizzy

Artifacts held by adjacent pets count towards your final score when you ascend.

Andrio

Sokoban prize closets that don't have the prize instead have mimics that imitate the prize.

ChrisE

When you finish eating a food ration while hallucinating, the game produces the message combination "That food really hit the spot! The spot hits the food ration. The food ration is destroyed!"

ChrisE

If a leashed pet falls down a trapdoor, the player may be able to pull it back out, depending on Strength and the weight of the pet.

lobbysob

Pets cannot move and eat in 1 action. Also, pets eating food off the ground merely makes it partly eaten, rather than completely destroying it.

aosdict, lobbysob

Alarm clock, which can be applied to set a time delay after which it will ring.

ChrisE

Fire trap effects, fire explosions, and camera flashes light up a larger area, but only momentarily, before it goes back to darkness.

nervous

Stacking too many uranium wands in a single object chain causes a huge explosion.

Zaha

Yellow dragon scale mail gives petrification resistance instead of (or possibly in addition to) acid resistance.

stenno, aosdict

Dreaming about more than just noises that are really happening: stuff like fantasy dreams where you dream that you ascend to the status of Demigoddess, etc.

ChrisE, Andrio

New or replacement (or hallucination-only) flavor-only message for magic traps: "Your spider senses are tingling!"

PsyMar, aosdict

Fizzy potions cure confusion when quaffed.

RGRN

Plumed helmets increase Charisma by 1.

RGRN

#sitting as a Monk enables meditation, which can have useful effects

RGRN

Allow closets to generate on east/west sides of rooms

RGRN

Digging into blobby engulfers splits them rather than reduces their HP to 1. (Still reduces HP to 1 on things like purple worms.)

RGRN

Electric eel corpses increase Pw/maxPw to an extent greater than newts.

RGRN

You get stoned when you faint while wielding a c corpse.

RGRN

Vomiting on an altar should offend its God, as should digging on it.

RGRN

Dragons have a smaller chance of leaving scales if they are killed with a sharp weapon.

RGRN

Shopkeepers refuse to deal with invisible customers completely.

RGRN

Silver variants of gear should cost more, and "precious" rings should have some kind of surcharge too, above the base cost of that type of ring.

RGRN

Wands of light should be weapons against vampires or all undead. Not to the extent of gremlins though.

RGRN

Digging tools should do double-damage against Earth-elementals, clay golems and stone golems.

RGRN

High level spellcasting monsters should have stone-to-flesh in their arsenal. Then they can use it on statues which come to life, always fighting on their side. They should also attempt to cast Charm Monster on your pets, with success inversely proportional to the pet's level.

RGRN

The description for the katana says it can be used as a two-handed sword. Maybe #twoweapon could be adapted for this, i.e. use both hands on the weapon for an extra damage bonus based on strength, at the expense of being able to use a shield.

RGRN

Cavemen get a large damage/to-hit bonus when throwing spears at large mammals.

RGRN

Asmodeus is a "cold" demon, so should not be visible with infravision.

RGRN

When polyselfed to foocubi of the appropriate gender, #monstering will seduce (i.e. de-robe) @ monsters.

RGRN

#Sitting on the floor messes up things written in the dust.

RGRN

Fire/Water elementals are not only uninjured by fire/water traps, but are strengthened/healed by them.

RGRN

All light sources, not just candles, should have stacked effects, so using multiple lamps illuminates a larger area.

RGRN

Foobanes scare the foo as well as causing extra damage.

RGRN

Beartraps injure your legs like xans do.

RGRN

The quest-text associated with the Sceptre of Might suggests it confers strength. So the +n Sceptre of Might acts like a +n ring of gain strength.

RGRN

You should have a greater chance of failing to write in the dust if your fingers are slippery.

RGRN

Wands of opening zapped down while in a beartrap should free you immediately.

RGRN

YAFM for when polymorphed into a glass golem and you rub a touchstone against "-".

RGRN

Apply '-' for a YAFM: "$(QUESTLEADER) always said you needed to apply yourself!"

RGRN

The appendage ("foreclaw") for a paper golem should be "forescroll" or "endpapers" or something.

RGRN

Death descriptions distinguish between "killed by a falling boulder", "killed by a hurled boulder", and "killed by a rolling boulder."

RGRN

Saving saves the previous N messages, so that one can find out what happened recently upon returning to a game after a long break.

RGRN

Option to make the confirmation letter "Y" instead of "y" so that you don't accidentally hit people when moving in the "y" direction.

RGRN

When two similar elementals are adjacent to each other, they may merge into one elemental with a higher level and higher hitpoints.

RGRN

Rangers can #chat to certain animalistic monsters to calm them and make them peaceful (but not tame). Possibly generalize this into a skill that can be achieved by Cavemen, Monks and Tourists too.

RGRN

Kicking a tree may generate one or more angry wood nymphs.

RGRN

Wood nymphs, or players polymorphed into wood nymphs, can walk through trees as if they weren't there.

RGRN

Zapping a wand of cancellation downwards while standing on a magical (magic, teleportation, polymorph, etc) trap will remove the trap.

RGRN

Drinking multiple potions of booze in a short time span has progressive effects: first confusion as normal, then vomiting, then sending the drinker to sleep or losing some (resistable) HP via alcohol poisoning. Also add in monster (dwarf, orc, leprechaun) booze-drinking behavior, complete with drinking songs as level sounds when a monster is intoxicated.

RGRN

Leprechauns steal potions of booze as well as gold.

RGRN

You can polish metallic shields by rubbing a towel on them. While it is polished and erosion-free, it provides reflection; but once it gets hit with some form of erosion it loses its polish and can't be polished unless the erosion is removed.

RGRN

Brass knuckles: = object that deals extra damage if unarmed and ungloved.

RGRN

If you eat a cursed C- or K-ration when hallucinating, you get an MRE YAFM: "That wasn't a meal, it wasn't ready, and you shouldn't have eaten it."

RGRN

Hitting a can of long worm or purple worm meat with an undead turning beam turns it into a can of worms, which when you apply or eat it creates a bunch of long worms around you.

RGRN

Rust monster corpses are untinnable, or else rust the tinning kit.

RGRN

Dropping a lit candle on a coaligned altar gives you some message about your standing with your god and your ability to pray safely. The candle is consumed in the process, and possibly the BUC matters (with a cursed candle plus an angry god ending in a fiery explosion). Some unspecified bad thing happens if you try this on a crossaligned altar.

RGRN

Artifacts occasionally resist being vaporized from overenchantment (however, if they do, they don't get the extra points of enchantment.)

RGRN

You have a lower chance of genociding monsters, wishing for items, and identifying canned food if you have never seen the monster or item in question.

RGRN

Reading a spellbook while confused may teach you a random spell but only set your memory of it to 1000 turns. It can also reduce memory of all other spells by 1000. Alternatively, it has no real effect, and just prints a message "You were holding the spellbook upside down... You learn the spell of 'kcol draziw'." (a random spell name printed backwards).

RGRN

When Schroedinger's Box is probed or has a stethoscope applied to it, it either reveals the housecat corpse inside or releases the live housecat as normal. Alternatively, stethoscopes give "You hear a characteristic WOM WOM WOM sound" as a reference to Bob the Angry Flower, and probing gives you "The box contains a cat that is neither alive nor dead nor alive nor dead nor...  You resolve to call the YSPCA later."

RGRN

It costs more money to donate to crossaligned priests for protection.

RGRN

Leprechauns steal credit cards as well as money.

RGRN

Credit cards act as holding containers for gold. Not literally, but if you have credit in a shop and apply the card towards the shopkeeper, they can put the credit on your card, which you can then use to pay at other shops. Paying with a credit card has a 3% transaction fee, minimum 1 zorkmid. Each card also has a "credit limit" which is the maximum amount of gold you can put on it. Randomly generated cards may have some (small) preexisting balance on them, but you might get the Kops called if you try to pass it off as your own, or if you pay with a cursed credit card. A possible evil extension is that occasionally your card is invalid because the owners took all the money and fled to [other roguelike]. Priests and demon lords cannot be paid in credit. Gold that you have on a credit card doesn't count towards score. Killing a vault guard zeroes all your credit card accounts.

RGRN

Shopkeepers gradually over time replenish their in-inventory gold, but only if Ludios is not yet generated. Any gold that is replenished to shopkeepers is removed from Ludios' large vault when it generates.

RGRN

A "money train" - a random event that spawns in a bunch of soldiers and giants carting chests of gold from the upstairs on a level to the downstairs.

RGRN

Eating a d corpse cures deafness.

RGRN

Tallow candles are edible and provide decent nutrition for a candle.

RGRN

Lit candles get snuffed when you move next to an unseen secret door, trapdoor or hole: "A hidden draft extinguishes your candle."

RGRN

Swimming while satiated can cause you to drown from stomach cramps.

RGRN

Moon phases affect the Plane of Water somehow.

RGRN

Water moccasins occasionally drop water walking boots.

RGRN

Trollsbane negates intrinsic or extrinsic aggravate monster.

RGRN

When you use stairs, not only do adjacent pets follow you, but any tame monsters adjacent to adjacent pets, and so on, also follow you.

RGRN

Scrolls of remove curse never generate cursed, and resist becoming cursed.

RGRN

Falling boulders (e.g. from scroll of earth) will smash fragile items lying on the ground on the square they drop on. Possibly rolling boulders do this too.

RGRN

Any sort of death by some sort of explosion should scatter the possessions around, rather than having a single bones pile stack.

RGRN

You can roll a boulder into the same square as a non-trapped flying monster.

RGRN

Priest characters get sanctuary in rooms containing unattended coaligned altars.

RGRN

#sitting on gold should be comfortable if you are polymorphed into a dragon.

RGRN

Erosion on rings and amulets makes their effect intermittent.

RGRN

Wand breaking effects that depend on the number of remaining charges use (charges+1) instead of (charges), to account for the wrest charge.

RGRN

The helm of opposite alignment has no effect on neutrals (except autocursing). Alternatively, some helms may turn lawful and chaotic characters neutral.

RGRN

If you are a Caveman, you get telepathy or clairvoyance while you are hallucinating.

RGRN

Gradually, over time, you lose points of Charisma due to accumulating dirt and scars and generally looking worse. This can be fixed with the usual restore ability methods, by entering water (possibly #sitting on fountains should do this), by getting hit by a rust trap (this only restores one point at a time), or by #wiping with a towel (which may have limited effectiveness).

RGRN

When you crush a monster who is carrying a wand with a drawbridge, the wand explodes.

RGRN

Chaotic same-race sacrifice demon summoning causes the demon to give you a nice item or some gold when they appear.

RGRN

Placing a fake Amulet of Yendor into any container blows it up.

RGRN

Flying is voluntarily controlled, not automatic. While flying, you burn nutrition faster.

RGRN

Whacking monsters with certain types of wielded scrolls may have certain effects on it (and may consume/shred the scroll in the process): fire burns them, confuse monster confuses them, scare monster scares them.

RGRN

The blessed potion of gain energy gives temporary sleep resistance.

RGRN

You can dip fruits (slime molds) in a potion of acid (or potion of water?) to turn it into a potion of fruit juice (consuming the fruit).

RGRN

When a pet eats a teleportitis-granting corpse, it randomly teleports (if possible).

RGRN

Dipping cursed unicorn horns into harmless potions turns them into harmful potions.

RGRN

Destroying a charged camera may spawn one or more yellow lights (or black lights if cursed).

RGRN

A boulder that falls on top of an altar destroys that altar.

RGRN

Leprechauns do massive damage to gold golems.

RGRN

Stealing or destroying a Nazgul's ring instakills it. Or possibly stealing reduces it to 1 HP.

RGRN

Attempting to light a cursed lamp or candle may burn your finger, dealing a little bit of damage: "Ouch! You burnt your finger!" (none if fire resistant).

RGRN

Potions of oil heal iron golems when quaffed.

RGRN

Non-fleeing soldiers grudge fleeing soldiers (they're deserters).

RGRN

Give cursed wands some bad effects other than rarely exploding, such as a cursed wand of fire also hitting your own inventory.

RGRN

TDTTOE: If it's possible to fooproof arbitrary items, fireproof candles are unlightable.

RGRN

Polying a crocodile corpse makes fireproof water walking boots instead of fireproof low boots.

RGRN

Soldiers are immune to fleeing because of low HP if they can see a higher-ranking soldier nearby.

RGRN

Dipping a blank scroll or spellbook into a potion of gain ability turns it into some random scroll or spellbook. The BUC of the resulting object uses the same formula as magic markers. Could also do this for wands of nothing, which become some random wand, without changing their charge count.

RGRN

Cavemen, Barbarians, and orcish players don't get the message "An urge to take a bath overwhelms you" from fountains.

RGRN

Quest leaders verbalize their confusion at the player's change of gender if the player has changed from their original gender.

RGRN

Vaporizing gear by overenchanting it abuses Wisdom.

RGRN

Barbarians feel angry, not sad, when a pet dies.

RGRN

Nurses rarely generate with stethoscopes.

RGRN

When a force bolt hits a huge chunk of meat, it turns into a bunch of meatballs (using the same formula for how many rocks are produced from a boulder).

RGRN

Being a male Valkyrie is a minor trouble when praying and will be divinely fixed by reverting you to female.

RGRN

Wraith corpses can be dipped into some potion to produce a potion of gain level.

RGRN

A diving helmet item which confers magical breathing when worn.

RGRN

If you are completely armorless, shopkeepers will block their door and prevent you from entering.

RGRN

Soul selling: when you summon a demon lord, there is some opportunity for you to sell your soul to them in exchange for a wish.
Selling your soul both angers your god and suppresses all interaction with them.
You may be able to recover your soul by killing the demon lord; for balance the demon lord should go far away when you sell your soul, though not out of the game.
Alternatively, unless you wish for nothing (which makes the demon lord vanish forever), the demon lord will immediately become hostile, making it an unlikely tactic in the early game.
Entering a temple without your soul will immediately anger the priest.
Your quest leader won't let you go on the quest while you are soulless.

RGRN

You can carve statues from boulders with a pick-axe.

RGRN

Occasionally, #sitting next to a tree will cause an apple to fall on your head.

RGRN

Creatures in pits are very hard to hit with projectiles.

RGRN

If a zombie finds a mummy wrapping, it will pick it up and transform into a mummy of that type.

RGRN

Mummy corpses never rot away.

RGRN

If you are lifesaved from attribute loss, it restores the attribute to its base value instead of 3.

RGRN

Water elementals have an active rust attack.

RGRN

Fish scale mail; awful AC but grants magical breathing

RGRN

Rogues get backstab bonus against any incapacitated enemy (sleeping/paralyzed) in addition to fleeing ones.

RGRN

Rings of regeneration are chargeable. While positively enchanted ones drain nutrition to increase your life, negatively enchanted ones sap your life to increase your nutrition.

RGRN

Tigers occasionally drop tiger eye rings.

RGRN

Swarm monsters which are invulnerable to weapon attacks and instead must be hit with area-of-effect attacks.

RGRN

Tinning the corpse of a named creature transfers the name to the tin.

RGRN

You have a small Dexterity-based chance of catching a potion thrown at you instead of having it break on you (this chance is zero if you cannot see the thrower.)

RGRN

Farlooking monsters tells you whether they are asleep, paralyzed, or fleeing.

RGRN

Dipping a wand of lightning in a pool of water electrocutes nearby monsters in connected pools of water, and possibly you.

RGRN

YAFM if you wish for "peace on earth": "Yeah, me too."

RGRN

The wish parser accepts "anything", "something", and "surprise me" as valid candidates for a wish for a random object.

RGRN

A troll killed via fire or acid will not regenerate.

RGRN

Swimming skill: how well you can swim on top of water and carry weight at the same time. At Unskilled you can carry very little, but it quickly increases beyond that.

RGRN

Message for when a pet (that you can see) gains a level.

RGRN

Digging downwards destroys any existing engraving on the square.

RGRN

When you or a monster digs a hole to a level below, rocks/boulders are created on the square you fall into.

RGRN

The rocks generated by smashing a boulder or statue should never weigh more than the boulder or statue.

RGRN

If you pray at low HP with a hostile monster in the vicinity, your deity might decide to "fix" the problem by smiting them to death.

RGRN

Water lily terrain: can be walked on, but if burned, rotted, or dug on, it turns to water.

RGRN

Falling rock traps are reflavored as thwomps from Mario if you are hallucinating.

RGRN

Ice boxes occasionally contain potions of booze or fruit juice in addition to corpses.

RGRN

Message for when a nymph finishes stealing something from you: "The [nymph] giggles and vanishes."

RGRN

Rooms are generated dark much more often when your luck is negative.

RGRN

A Big Room variant that is an idyllic scene with a nice river cutting through it with some scattered trees and maybe a couple fountains and a lake. Idyllic except for the usual bunch of monsters, of course.

RGRN

Rocs: large, rideable, fast and powerful birds.

RGRN

Thunderbirds: birds with lightning breath.

RGRN

Phoenixes: birds with fire resistance and who may automatically resurrect on death, or else revive from their corpse/ashes similar to trolls.

RGRN

Forest rooms, which contain a scattering of trees.

RGRN

Wind trap: when you step on it, your wielded weapon and any items on the square are blown up by a gust and fall back on your head.

RGRN

Hitting monsters with a passive shock attack doesn't do anything if you're hitting with gloved hands or a non-metallic weapon.

RGRN

Booze is a customizeable name in the options like fruit/slime mold.

RGRN

Exercise or abuse Charisma as a result of consorting with foocubi.

RGRN

You get a small Pw boost (similar to newts, or perhaps not boosting max Pw)? by eating the corpse of a spellcasting monster.

RGRN

When you are both hallucinating and weak from hunger, monsters start appearing as&nbsp;% instead of regular hallucinatory glyphs.

RGRN

Add fruit in tins as an alternative to spinach or corpses.

RGRN

Boost healers' starting Dexterity; they should be better at delicate surgical procedures than the minimum Dx:7 implies.

RGRN

Vomiting erases any dust engravings on your current square.

RGRN

Decorative objects/furniture for atmosphere: sarcophagi, (inanimate) skeletons, rubble in corners, mist, shafts of light that illuminate small areas.

RGRN

Abort a multi-turn search when something is discovered.

RGRN

YAFMs (both regular and hallucinating) for #sitting on the Vibrating Square. Something to do with a vibrating chair massage.

RGRN

Monks can forcefight or kick boulders and break them with high enough Strength.

RGRN

Track, and report at the end of the game, how many times the player prayed and sacrificed.

RGRN

Penalty (alignment? luck? aggravate monster?) for eating a coaligned unicorn.

RGRN

Cavemen get a small penalty for writing or using complex tools.

RGRN

Padded sack: bag that protects its fragile items from breaking.

RGRN

Fragile items get smashed by falling to the ground while dying or passing out or falling downstairs.

RGRN

Armed bear traps and land mines can be teleported away if hit with a teleportation beam.

RGRN

Eating a disenchanter corpse sets Pw to 0.

RGRN

You can fill a pit by dumping sufficient rocks in it.

RGRN

The three unoccupied corners of the Castle contain mimics mimicking chests.

RGRN

Vortices, or possibly all whirly monsters, scatter items to different squares when they pass over them (using the throwing code, so items may shatter and creatures may be hit by them).

RGRN

Magic missiles, and possibly other rays, stop at the first creature they hit and don't continue to other creatures behind it.

RGRN

Backstabbing can additionally occur if you are stealthy and the target monster does not correctly know where you are.

RGRN

Replace blessed genocide's class genocide effect with one that lets you name multiple species not from the same class.

RGRN

Lesser and greater scrolls of enchant weapon. The lesser enchant by 1 point up to a maximum of +2 (uncursed) or +3 (blessed); the greater enchant by 1-3 points to a maximum of +5 (uncursed) or +7 (blessed).

NeroOneTrueKing

Multi-skill gifted weapons should unrestrict all of their skills.

dNetHack

Tarmunora

Confused scroll of consecration consecrates your weapon, which blesses and fooproofs it and maxes/increases its enchantment with no possibility of evaporating. Possibly, turn it into an artifact as well.

NeroOneTrueKing, aosdict

The Staff of Aesculapius doubles healing from all sources while wielded.

Tarmunora

Italchiayaque can be read to get a clairvoyance mapping, with the message "You see nearby terrain reflected in the depths of the shield."

Tarmunora

The Master Key of Thievery can be wielded and makes 3-4 stealing attempts per hit. Alternatively, it can be wielded in the offhand while twoweaponing and make 1-2 stealing attempts per hit.

Tarmunora

Shepherds' crooks: a wooden multi-purpose weapon-tool.
Damage is a little less than a quarterstaff. Should probably not weigh as much as a quarterstaff; it would be hard to justify 40 weight any way you slice it.
Can be applied to give a menu offering to do one of three things (and unlike grappling hooks it never does the wrong thing):
Hit a monster at polearm range (skill-dependent).
Attempt to hook a monster at polearm range. Tame monsters are always hooked. Peacefuls are always hooked, but may be angered. Hostiles might be hit instead of hooked. If the monster is hooked, it will be pulled towards you, or you will be pulled towards it if it's much larger than you.
Grab the top item from a square, even if the square is a trap or water square.
Wielding one passively gives a boost to the radius in which pets will follow when you change levels.
Wielding one also makes pets follow you as if you had a treat.
Can be applied to a monster two squares away to yank it towards you, which may stun the monster.
Binders in dNetHack could start with one. Peasants in dNetHack could generate with them.
Two-weaponing a crook and a flail should do something (from Egyptian pharaoh iconography).

Chris_ANG, aosdict, AntiGulp

Inside the Wizard's Tower, the player encounters some of the Wizard's hostile apprentice wizards.

K2

Player monsters can pray and become invulnerable and have their problems fixed by their god.

FIQHack

bug_sniper

If the player is strong enough and able to pick up a sink off the floor, it actually works: they rip it off the floor and water floods the room.

SporkHack

AmyBSOD

Rebalance multishot damage so that multishooting +7 projectiles doesn't give a massive damage bonus over a single +7 melee weapon. Possibly only apply the damage bonus to the first projectile.

ais523

You can consolidate wands of the same type by rubbing them on each other. This transfers one less than the number of charges in the wand (or just 1 charge if the wand has only one charge), and increments the recharge counter of the new wand. Overcharging a wand like this beyond its normal generation limits may make it explode.

Muad, aosdict, K2

Tourists begin the game with walking shoes.

jonadab

When you complete your Quest and return the artifact back to your Quest leader, and if you return to them with the Amulet, you are rewarded with a (one-time) hero's feast. This restores HP and fills your nutrition to just below Satiated (and increments the turn counter?)

bug_sniper

If you have enough Str, you can dig with your bare hands, but it takes much longer and may incur HP damage.

AmyBSOD

Restore ability sources (including unihorns) only restore stat points up to their starting values, not to the highest values reached. Alternatively, restore up to the average of the starting and maximum value, rounded down.

Lymia, jonadab

An unaligned alignment quest.

SLASH'EM

ais523

You can't produce more holy or unholy water by dipping. Instead, each water can be dipped into a largeish but finite number of times.

Chris_ANG

Random killer bees always spawn female. Male ones can only generate in beehives.

FIQHack

aosdict

Instead of instakilling, death rays cause a delayed instadeath that require consumables or prayer to fix.

ais523

Figurines cost 50 times their monster's base level (or some other constant).

raisse

Subspace branch, which has many entrances and exits to various parts of the dungeon for quick traversal. However, it's populated with nasty monsters.

AntiGulp

Bird pets are better at combat than mammals, but can carry much less due to weighing less.

SpliceHack

aosdict

For most calculations that involve the depth of the Sanctum (score, level difficulty with the Amulet) use a constant 50 in place of the Sanctum depth.

aosdict, AntiGulp

Drop bears: possibly t-class monsters that hide on the ceiling, generating next to or near trees. They are unimpressive in combat, except for the nasty amount of damage they deal with their initial dropping attack. Can only go back to hiding when next to a tree.

aosdict, jonadab

Rework hard helmet mechanics so that for large objects like boulders, they only take a few points off if anything.

aosdict, raisse, dracunos

If you're polyselfed to a lithivore, worthless glass tastes terrible but valuable gems taste delicious. Each gray stone gives a different YAFM: "Yabba-dabba delicious" for flint, "That was a heavy meal" for loadstone, "The stone's texture is delightful/distasteful" for touchstone,&nbsp;??? for luckstone.

aosdict, greqrg, FIQ, rikersan

Some means of leaving an engraving on the ground for the next player who reaches that floor to encounter (not a bones file, just a random engraving).

Pavel

The game opening text for certain roles is changed from "It is written in the Book of [deity]:"
Caveman: "It is painted in the Sacred Caves of [deity]"
Valkyrie: "It is sung in the Sagas of [deity]"
Wizard: "It is inscribed in the Tomes of [deity]"
Barbarian: "It is carved on the Stone Tablets of [deity]"
Archeologist: "It is written in the ancient Scrolls of [deity]"
Priest: "It is taught in the Temple of [deity]"

aosdict, Mandevil, stenno

When an imp says "Look! Thy bootlace is undone!", he might tie your shoes together and cause you to fumble for d10 turns.

Muad, aosdict

Spellcasters who curse items also have a separate way to remove your knowledge of items' beatitude, so you don't know what might have just been cursed.

ais523

If you have been crowned, you can trade your crowned status for a wish. (You still keep the huge prayer timeout though.)

Wooble

Add un-eroding a dipped item as an additional fountain dip effect.

aosdict, vent

Muzzles that can be put on pets so they stop eating food off the floor. Uncursed ones block their eating 90% of the time; blessed 100%; and cursed ones weld to the pet's face and prevent it from eating anything until it starves or the curse is removed.

lollyde

When Fire and Frost Brand come into contact with water due to rust traps or dipping them in fountains, print a message about the water instantly evaporating or freezing. If either is dipped into a fountain, it dries it up.

Luxidream

When either 1) you are hallucinating and hit something well enough to have gotten a&nbsp;! on the hit message or 2) hit something with a type weakness (fire versus cold-resistant, cold versus fire-resistant, electricity versus water, etc), an additional "It's super effective!" message is printed.

aosdict, ais523

If you drown as a Pirate, the death message is changed to "went to Davy Jones' locker".

dNetHack

aosdict

Scroll of material change, which converts the material of an object into a different one.

Object materials patch

Escaity

If you hit a cockatrice with a corpse of a non-petrification-resistant monster, the corpse turns into a statue.

ChrisE

Command to tip all items from one container into another container.

ChrisE

Add nets, on the basis that NetHack needs to have nets in it.

Masterjun

All acidic corpses, not just acid blobs, never get tainted (but do eventually rot away).

rikersan

Statues generate in throne rooms, because they are the sort of thing a throne room would have.

ChrisE

For variants with wand skill, higher wand skill improves the outcomes from snapping a wand. Ideas include increasing the effective number of remaining charges, increasing the explosion radius, and decreasing the damage the player takes.

Tarmunora

Rings carried by Nazgul are all artifact rings of invisibility. They autocurse and also confer telepathy, see invisible and aggravate monster.

picaresquieu

Rodneybane weapon: has a giant bonus against the Wizard (only) and negates the Amulet's extra Pw drainage. Located in some heavily guarded location.

K2

#chatting to monsters gives different various effects depending on your current form and the other monster. For instance, chatting to an orc as an elf or vice versa will make them hostile.

AmyBSOD, PavelB

If you're invisible, peaceful monsters may bump into you and get mad.

AmyBSOD

Poisonous tree frogs, which only generate in trees. Applying darts or arrows to them can coat the darts or arrows with poison, but the poison can also get on your hands.

K2

Dipping or dropping zorkmids in a fountain very rarely increases your Luck.

PavelB

You can leash peaceful and hostile monsters, but peacefuls will turn hostile, and they will attempt to get the leash off.

AmyBSOD

Artifact Callandor, a glass long sword or crystal sword in dNetHack. Lawful, provides double spell damage when wielded. Possibly only gifted to male characters.

aosdict, rikersan

Slime terrain or puddles of slime, left behind when Ps move around. It either deals damage or erodes footwear to stand in it.

PavelB

Caltrops: a nonmagic tool with multiple charges that creates a "caltrop trap" on your space, which damages / immobilizes / slows the first monster to enter it. Rangers and rogues excel at using them and possibly get some bonuses from them.

bouquet, aosdict

Genociding part of an amalgamation turns the monster into a non-amalgamation of whatever its other half is.

SpliceHack

AmyBSOD

Bluff monster: a shapeshifter that is biased towards powerful forms and nasties, but it actually retains the weak attacks and HP and AC of its regular form.

Luxidream

You can #pray at a gravestone, or possibly ring a bell at one, to cause any of a number of good and bad effects:
Summon a ghost, which might be hostile or peaceful.
Summon a hostile undead, flavored as it forcing its way up out of the grave. Usually a zombie.
Polymorph you into a zombie or mummy of your own race.
Put you to sleep, ignoring resistance.
Create a swarm of hostile manes or lemures.
The headstone falls on your foot, dealing some damage, less if wearing boots.
If the grave is a bones pile grave, the ghost of the player always appears. It will be peaceful if their alignment matched your own and hostile otherwise.
Various cosmetic messages that do nothing. "The air suddenly turns cold." "The engraving on the headstone shimmers for a moment."
The dirt cracks open and spits out any items buried under it.
A voice from nowhere whispers a random rumor, true or false.
The epitaph on the grave changes. This does not flag the grave.
Get an alignment bonus for honoring the dead (this is only if triggered by #praying). "You feel that the one buried here is content." Bonus might be larger if you're lawful or a Priest, probably 1 otherwise. This should possibly happen before and independently of any other effects.
Limited identify of 1 item.
Type-identify of multiple un-type-identified items in the inventory, but the player doesn't get to pick which. Might pick 0 items (flavored as the spirit not knowing anything new about what the hero is carrying).
Enlightenment.
Temporary telepathy / sleep resistance / infravision / other intrinsic.
The gravestone rumbles and moves aside, revealing a branch staircase to a just-created-now one-level branch, a small one-off "crypt" floating branch that contains some undead, some boxes containing corpses, and some treasure.
You "feel that the dead are restless", aggravating monsters level-wide. All gravestones on the level become flagged against further attempts. This effect could be added to and independent of other ones, and if so, it's a chance dependent on the number of already flagged gravestones on the level, which provides a nice way to balance it on levels that have massive amounts of gravestones.
After you get one effect, the gravestone is flagged so that it doesn't happen again (or, more evilly, that any further attempts will only result in bad effects). Possibly shouldn't work at all on graveyard levels, because they have too many graves to balance these effects. 

aosdict, PavelB

Alarm trap on doors: it makes a noise to alert nearby monsters, and also summons a squad of ogres or Kops or whatever on one of the stairs.

xNetHack

AmyBSOD, PavelB

Circus artist role. You can tame circus animals like tigers, catch incoming missiles with your bare hands, and jump over bottomless pits.

AmyBSOD

The game logs the number of attempts the mysterious force triggers, so that it can be observed and analyzed later.

AmyBSOD

Magic lamps and regular lamps can generate as various different materials. For rare material variants, a djinni that comes out of a magic lamp of that material and grants a wish will return back inside it one or two times, thereby granting multiple wishes.

Object materials patch

aosdict

When potions break on the ground, they leave puddles of that potion. Pets can drink this puddle to get the effects. They also give effects (vapor effects, plus acid burning) to any monster standing in them, which is nice because it makes it harder for the player to stand in one place and fight a horde of enemies. Not defined what should happen if multiple potions mix in one spot - alchemize perhaps.

raisse, AmyBSOD, aosdict

The weight of your character varies depending on your hunger status.

winny

Command that marks a given map square with something that's visible on the map but doesn't exist in the actual game.

ChrisE

If you wield a c corpse and take any of several actions that normally turns you to stone, it instead rolls a body part to see which part of you touches the corpse. If this part of you is wearing armor, you don't touch it and so don't turn to stone. However, it's impossible to cover yourself completely.

AmyBSOD, aosdict

Once you enter the Fort Ludios vault, several guards or Kops will appear from the portal and try to come hunt you down.

AmyBSOD

The treasure found in random graves should be more treasure-like or the sort of items that get buried in graves in real life, rather than just random objects.

stenno

Fire giants can walk through lava. (Probably an addition to the "all water is fairly shallow so all giants can 'swim'" idea.)

greqrg

Silence auras that prevent both you and monsters spellcasting. Maybe also a directed silence spell, which silences an individual monster. While silenced, monsters can't be #chatted to.

ais523, aosdict

Instead of infinite rechargeability (that opens up a lot of exploits and farming like smoky potion farming and infinite altar farming with the Platinum Yendorian Express Card), horns of plenty now stop being rechargeable after 7 recharges.

aosdict, stenno

When you are polymorphed into a sea monster, you can sit on fountains and drink potions of water to regenerate HP.

PavelB

Give a YAFM when near or chatting to a hallucinogen-distorted leprechaun: "They're after me lucky charms!"

Demo

Armor made of bone increases your spellcasting ability somehow (many ways to do this; decrease failure rate? Decrease Pw cost?)

object materials patch

aosdict

New artifact: The Trident of Poseidon. Chaotic (only because Poseidon is in-game). While carried, grants magical breathing, swimming, and protects items from water damage. When wielded, confers water walking. Double damage versus aquatic monsters, and gets a damage bonus versus all that scales with the amount of water squares adjacent to you. Invoke to get an UnNetHack-style flood.

aosdict, PeterQ, Demo

When you throw ammo without the proper launcher, the game makes it clear that you're doing it wrong, e.g. "You clumsily throw the arrow". This also abuses Wisdom.

Luxidream, ais523, aosdict

If you stack up too many extra movement points from scrolls of time, time freezes even for you, and your game ends with the killer reason being "became frozen in time".

SpliceHack

aosdict

Wearing armor made of gold increases your Charisma by 1 or 2 for each piece worn (possibly even bypassing racial maximums).

object materials patch

PavelB

The hood on a worn dwarvish cloak will protect your helm from getting rusted.

Luxidream

All instances of "mysterious force" are changed to "normal force" when you're hallucinating.

Andrio

Whether an artifact has or hasn't yet cooled down is visible to the player.

Luxidream

Closed-for-inventory shops, if you encounter them again on the ascension run, will now be open.

bouquet

If Aeglos/Aiglos, the Spear of Gil-galad, is ever implemented, it should have cold-related effects, because it means "Snow-point".

elenmirie, aosdict

Reading a scroll of knowledge while confused or hallucinating gives you enlightenment instead.

SpliceHack

aosdict

Give a different message for when you injure your legs by kicking. Possibly as subtle as "Ouch! That really hurts!", but could be more explicit like "Ouch! You injured your leg!"

PavelB, aosdict

Object property "frost walker", which only generates on boots. When worn, lava cools into solid floor and water freezes into ice in a radius 1 around the wearer. Optional if they unfreeze afterwards. Alternatively, make this an artifact pair of water walking boots.

aosdict, PavelB, raisse

Pits (and other traps?) on early dungeon levels are sometimes pre-mapped.

greqrg

Ghosts lose their physical touch attack in favor of a reusable attack that scare-paralyzes you. Possibly, if this is unflavorful due to it just being the same ghost, change their AI to make them turn invisible after a certain amount of time being visible and not next to the player. Then they path towards you, and if you either stumble into them or they are next to you and get a move, they turn visible, paralyzing you. Since the actual action of them appearing out of nowhere would be what frightens you, see invisible would negate the effect.

aosdict, oh6

Confused scrolls of wishing let you wish for a terrain type that appears under you, like in wizard mode.

Fourk

aosdict

Ranged attacks get an accuracy bonus if you rested the previous turn.

jonadab

Wearing gauntlets of power, you can snag a boulder and pull it with a grappling hook. If in Sokoban this incurs a penalty.

bouquet, aosdict

If you manage to get an aligned priest to wear a helm of opposite alignment, he becomes a priest of a different god. (Not defined what this should do to Moloch priests; maybe their heads explode?)

isha

You can apply an empty expensive camera at a yellow light to recharge it.

Wooble

Archeologists (maybe gnomes too) start the game with all valuable and worthless gems (but not gray stones) identified. If this is too powerful, perhaps they only begin the game with all worthless glass identified.

Vivvy, Wooble, aosdict

Asmodeus' cold attack can freeze potions in containers.

Wooble

Fix flavor of steam vortex messages. "You're being boiled alive!" and "Mmm, a sauna" if fire resistant. If you aren't carrying a towel, "You wish you had brought your towel to the sauna".

raisse, attie

Make the Wizard of Yendor's corpse always taste terrible.

raisse

Ravens flee from straw golems, who are basically scarecrows.

PavelB

Checkerbug: like a grid bug, but can only move diagonally.

FlamingGuacamole

If polyed into a giant, you can pick up a door off its hinges (breaking it).

greqrg

Extend the Advent Calendar patch to include Hanukkah gifts: behind the same appropriate doors depending on the date in December, you can find candles and potions of oil. If mundane candelabrums are added, possibly add those too.

aosdict, bhaak

Engraving (or ward) that is bad/cursed, and it causes bad things to happen on or around it. Anti-Elbereth of sorts. Monsters may deliberately engrave it to hurt the player.

aosdict, PavelB

Make the Castle not a graveyard level, and compensate for this by altering wraith corpse drop odds somehow.

bug_sniper

Spells can be "bound" together so that they can be cast simultaneously.

AntiGulp

When a monster wears a helm of opposite alignment, it becomes tame if it were hostile, hostile if it were tame, and either hostile or tame depending on the helm if it were peaceful. When it removes the helm, it undergoes a fresh peacefulness check as if it newly generated.

Chris_ANG, aosdict

Put a ranger corpse named Narcissus, and a flower if possible, on Echo's level.

dNetHack

aosdict

Quaffing cursed invisibility removes the invisibility intrinsic if you had it. Possibly the same for see invisible.

AmyBSOD

Seduction may not work if the seducer is invisible.

Luxidream

Monsters apply mirrors at you if you are a nymph or umber hulk.

FIQHack

bug_sniper

When riding, your steed may randomly go in a different direction than you intended. Higher riding skill decreases this, and expert blocks it entirely. Possibly, the steed will use this ability to shy away from water or other known hazards.

AmyBSOD

Customizable, player-named "hat" armor that uses a similar system to slime molds, except it is 0 AC helm-slot armor. Archeologist fedoras are set to this by default, and the fedora item is removed and replaced with the more generic "hat", which is hard-set to fedora for Arc's starting hat.

Chris_ANG

Luggage pet for Tourists. Has very high carry capacity and doesn't drop items of its own accord. Fights like a normal pet. Either it is immune to damage but has a low maximum level to compensate, or if overwhelmed, it doesn't die but instead turns into a normal "luggage" object that will eventually reanimate.

Chris_ANG, aosdict

Spell that creates temporary weapons and armor made of energy: good base stats, but no magical properties, and vanish after some amount of time. Not defined whether they should be enchantable; probably they should but the enchantment will vanish along with the rest of it.

Demo

Monks, and possibly other roles, can learn martial arts techniques out of spellbooks similar to dnethack wards and SLASH'EM bard spells.

Chris_ANG

Leashes show on the map so you can tell where a leashed invisible pet is.

Wooble

Weight the probability of Orcish Town down lower than 1/7. Possibly as a starting point, reintroduce Frontier Town as minetn-8 so that the probability will become 1/8.

ais523, greqrg, aosdict

Losing alignment makes it permanently harder to regain alignment. Do this by instead of using a linear scale where current alignment equals alignment gained minus alignment lost, use a ratio where current alignment is alignment gained divided by alignment lost (probably with some constant factor in there somewhere).

ais523, ChrisE, aosdict

F corpses can be dipped into potions to make different potions: juice + violet fungus = booze, juice + yellow mold = sickness, water + green mold = acid. (Note the existence of the Brewing Patch, which dissolves most F in juice to produce confusion, hallucination, booze, sleeping, and healing.) Later suggested recipes which involve dipping a corpse in acid to dissolve it:
Wraith corpse -&gt; potion of gain level. (Does not always succeed, to compensate for the fact that a wraith corpse doesn't always grant a level. Maybe it even has a lower success rate than getting a level from a corpse.)
Newt corpse -&gt; potion of gain energy.
Floating eye corpse -&gt; potion of levitation or possibly monster detection.

RGRN/Malcolm Ryan, aosdict, ChrisE, Luxidream

Up the chance for a wish for a wand of wishing giving you a wand that contains one more wrestable wish, to 50% or 75%.

ChrisE

If you used to have the Amulet but now don't for some reason, your death message gets "(without the Amulet)" appended to it.

ChrisE

When beginning the game in permahallu mode, after the "welcome to NetHack!" message, give the message "NetHack is filmed in front of a live studio audience."

variants with permahallu mode

aosdict, _Q

New random true rumor: "Tho' from men's hearts doth it evoke the worst, accursed gold is neither blest nor cursed."

vivit

Gloves that give a boost to multishot somehow: either increase the maximum by 1, or reroll the roll if it happened to be 1, or something. There's debate on how not to overpower multishot with an item like this.

nooodle, aosdict

Non-weapon stethoscope skill, which gives less information than it currently does at Unskilled (perhaps just HP), the same amount of information as currently at Basic, more information like pet tameness and apport at Skilled, and a full probe at Expert.

nooodle, aosdict

AC you have from your polyform should not stack with AC you have from armor. The game should compute both, take the max, and then add on AC from other factors like protection.

Chris_ANG

Glass doors that you can see through and kick to break with ease.

NeroOneTrueKing, aosdict

Generalize health food stores into a special type of role-specific shop. This shop isn't an actual shop; it signals the level generator to transform it into a different specific type of shop depending on the player's role. The role-specific shops contain role-helpful items like health food does for Monks. They can be found randomly generated with probability around 5%. If a role doesn't have a specific type of shop associated, the shop becomes a general store instead.

aosdict, Demo

Doppeldoll: an artifact figurine that when applied turns into a tame clone of yourself with copies of all your weapons and armor.

rikersan

If you attack a monster while standing on Elbereth, all monsters in line of sight stop respecting Elbereth.

ShivanHunter

Non-cursed rings of hunger don't drain excess nutrition when you are Hungry, and slow digestion rings don't slow your digestion when you're oversatiated.

bug_sniper

Resistance rings, if worn while using barehanded ungloved combat, get a damage bonus of the elemental type they provide resistance to.

Demo

Armor of lifesaving. Works as expected; more interesting than an amulet because it leaves you more vulnerable after disintegrating. This could possibly be an (extremely rare) object property.

Chris_ANG

Various alternate endings for the game:
You can take over an abandoned shop, stock it with items and mimics, and settle down as a new shopkeeper, ending the game. This creates a bones file with you replaced by a shopkeeper bearing your name.
You can eradicate the Wizard of Yendor from the game entirely and forever, becoming the next Wizard of Yendor yourself. This is done by standing in the center of the Wizard's Tower wearing the Amulet of Yendor and invoking it. This respawns a beefed-up Wizard; defeat him and the game ends with you as the next Wizard. (It's missing an end condition for what happens if you escape the dungeon while in this semi-powered-up state.)
You can claim the Amulet's power for yourself rather than giving it to a god. While anywhere on Astral, invoke the Amulet while wearing it. You get some big and unspecified surge of power from it. Furious at your betrayal, your god smites you every way they can, joined in by the other gods and the Riders, calling to bear all their priests, angels and Archons, which spawn in swarms on the high altars. (You also lose sanctuary.) You have to reach each high altar and shut it down/destroy it. Once you have done this, you win and keep the Amulet's power for yourself, as long as you can manage to hold on to it.
Alternatively, there is another way to do the "claim the Amulet for yourself" way: once you invoke the Amulet, a timer starts. The gods have only this much time to kill you or take the Amulet away before you become invincible to them. Would require some anti-boulderforting measures though. Or, you have to escape the Astral Plane back to the surface wiht all the gods trying to impede your progress.
You want to break the power of the Amulet so no one gets it, and break the gods' dominion over the world. You must #invoke the Amulet while standing on each high altar to destroy it. (Not mutually exclusive with the other ending: you don't channel the Amulet's power into yourself, but into the high altar. In a game with both endings, you trigger the other one by invoking it anywhere except a high altar.)

bhaak, aosdict, jonadab, K2, ShivanHunter, [1]

General artifact-stealing attack; like the Wizard's quest-artifact-steal attack but applicable to all artifacts and without Amulet of Yendor theft baked in. Archeologist player monsters might use this ("That belongs in a museum!").

aosdict, Luxidream

Inflicting poison damage on a monster, or killing it by poison, makes the corpse poisonous to eat.

greqrg

You can dip an item in a ochre, spotted jelly, or acid blob corpse to make it take acid damage (if applicable).

K2

Because general stores will buy anything, they will only buy stuff at 1/2 or 1/3 of its usual sell cost. To obtain the full cost you have to sell items at a specialized shop of their type.

AmyBSOD

When a monster wields Vorpal Blade out of your sight, you hear "a distant snicker-snack".

nooodle

Hallucinatory trap names for when you look at traps while hallucinating: "slime pit", "jack-in-a-box", "buzzsaw trap", "spiked floor", "axeblade trap", "queasy board", "revolving wall", "uneven floor", "anti-anti-magic field", "ice trap", "finger trap"

aosdict, K2

Vorpal and bisecting weapons don't get dull when you engrave with them.

rikersan

Alchemic golem, which is basically made out of potions. Its melee attacks expose you to random potion or potion vapor effects. Killing it drops a few random potions and causes more random vapor effects. It can spontaneously explode when it hits something, with a greater chance when you hit it in melee. The explosion obviously also causes multiple random vapor effects to the area, and scatters potions around (by throwing them, so they tend to smash if they hit anything).

Chris_ANG, aosdict

Some, most, or all roles begin the game with high or maxed Luck. Of course, without a luckstone, this times out over a few thousand turns.

jonadab

Cavemen (maybe only lawfuls) get a small bonus for cannibalism, because it is honoring the ancestors.

rikersan

Amulet of reincarnation: when you die, saves your life, but permanently polymorphs you into a different form.

AntiGulp

When an egg gets very, very old, it cracks and releases a small stinking cloud. If it happens to be carried by the player, the cloud centers on the player. When it is within 100 turns of cracking (or perhaps just after it's gone rotten), the player can throw it and it will release the stinking cloud wherever it shatters.

aosdict, Chris_ANG

Thrown potions of sickness create a stinking cloud centered on the spot they break. If the potion were diluted, the cloud is either smaller or disperses faster.

Chris_ANG, aosdict, Vivit

Potions of sickness induce vomiting, which can be used in a pinch to cure food poisoning or overeating.

inari

When you have a slower pet leashed, slow down _ travel by resting whenever you would move far enough from the pet to pull on the leash.

jilles

You can climb into and hide inside large boxes.

reaver

Delicatessen shopkeepers chide you if you eat something while in their shop that doesn't belong to them and that you didn't buy from them. "Buy something or get out!"

aosdict, bouquet

Boulders tear through spider webs (whether from a rolling boulder trap, thrown by a giant, or pushed by the hero).

AntiGulp, aosdict

King Arthur gets the same resistance suite that the player gets for crowning, and the Grand Master and Master Kaen get the suite of intrinsics that high-level monks get.

Chris_ANG

Usage fees can never exceed the original cost of an item, and when you buy the item, any usage fee is removed (it's only charged if you use the item without buying).

bug_sniper

When polymorphed into a paper golem, you can't write on the floor with your finger because it would get too dirty.

Menche

Desks as dungeon furniture: they can store items like a container, and acts like a table if you are on top of it (if levitating you can interact with it and things on it). Sometimes generates a magic marker inside. Writing scrolls or spellbooks at a desk has some bonus: maybe a higher chance of writing unidentified, or a slightly reduced or capped ink cost. Possibly put one or more in the College of Archaeology, and Warden Arianna's office for Convicts.

Chris_ANG, aosdict

Unconsecrated or minor altars. They are either to some unnamed lesser god, or to no one in particular. They can be converted to your god like normal, but don't have any penalty for kicking or attempting to engrave or anything while still unconsecrated.

aosdict, ais523

Structure speed on a four-tier system: normal, fast (available intrinsically), very fast (available extrinsically via speed boots), and extremely fast (available only via consumables).

ais523

The Amulet of Yendor blocks teleporting within a dungeon level, but only after a certain radius. Short-range teleports work fine.

Chris_ANG

If you apply a mirror at an empty square and that square is a "corner", you gain temporary vision in the perpendicular line around that corner. If it's a T-junction you look both ways. There is a "Done." at the end like detect monsters has.

aosdict, raisse

Applying a pruning hook (or possibly any polearm) to a space containing a tree, assuming there's no monster occupying that space, it triggers the regular bees/fruit from the tree without needing to kick it.

aosdict, jonadab

The Longbow of Diana has different effects based on which alignment you are (or perhaps it's just different artifact bows, only one of which appears). Lawfuls get an Apollonian bow which shoots gold arrows which have higher base damage. Neutrals' bow fires silver regular arrows. Chaotics' bow automatically poisons fired arrows.

rikersan

Intrinsic teleportitis is no longer binary; you build it up by getting the intrinsic from multiple corpses. With more of it built up, the random teleports happen more frequently. However, the effect wears off over time and eventually fades completely (with some message like "You feel less jumpy", so the hero knows they can't Ctrl-T at will anymore).

aosdict, jonadab

Allow Rangers to advance bow skill to Master.

jonadab

Make the breakage rate of ammo tied to the player's skill cap in its corresponding skill. This incentivizes roles which start with ammo to use it rather than finding a subpar melee option.

jonadab

Allow sufficiently skilled characters to multi-fire while levitating.

jonadab

Gillyweed: comestible that grants temporary intrinsic magical breathing when eaten.

Demo

Thick woolen socks, worn in the boot slot. Give no AC, but provide cold resistance.

PavelB

Deafness protects against cockatrice hissing and therefore their stoning. (This might be too powerful; it might need to just reduce the chance of stoning rather than eliminating it altogether.)

jonadab

When applying a mirror at yourself, give different messages depending on your race, gender, and charisma.

Vivit

Dogs are buffed to be better fighting than cats as a starting pet, but lose their ability to curse detect.

Vivit

You can stomp your foot by kicking at the ground. This causes noise around you depending on how much weight you're carrying. Cannot be done over a certain encumbrance.

Vivit, aosdict

Give a YAFM if you would "sink like a rock" while currently turning to stone.

Chris_ANG

Samurai can wield katanas, wakizashis, and sabers in zero turns.

Vivit

The spellcasting menu automatically (by default) assigns letters to spells in a fixed order, rather than alphabetically in the order the player learned them. For instance, ordering by school, then by ascending level, then by name. Or even just in objects.c order. This guarantees that unless the player rearranges the menu, they will always have the same letters from game to game.

Andrio

If controlled teleportitis triggers while you are _ traveling, the cursor is automatically placed on where you had specified to travel to.

Andrio

Playing a wooden harp (and possibly a wooden flute) near intelligent peacefuls may cause them to give you some money or items from their inventory, but there's also a chance that they become hostile (without an alignment penalty though).

ais523

You can invoke the Amulet on Moloch's high altar to destroy it; this does something good later for you (more points? prestige?) but Moloch will now harrow and hound you down all the way back through Gehennom even more fiercely than usually.

aosdict, Mandevil

When a container containing items is polymorphed, it can only turn into other containers (possibly never a bag of holding to prevent abuse). Or else the contents just get spilled out (and possibly polymorphed themselves).

aosdict, ShivanHunter

A greased object thrown across the floor will slide an extra 2d4 spaces.

K2

Hitting a fountain with a ray of cold or cold blast freezes and breaks it, creating frozen pools in the area.

raisse

Breaking a wand of wishing will wrest it if possible.

AlbertB, rikersan, Luxidream

If you escape the dungeon, a short blurb prints describing your post-dungeon career. This factors in your material wealth (gold, gems, and other things you escaped with), deity anger (they will be mad at you for abandoning the mission regardless, but if already angry before your escape you will not live long outside the dungeon), and alignment record (bad alignment could cause you to get spurned by your peers), along with possibly more factors.

Luxidream, aosdict

When remove curse uncurses things in your inventory, those things glow amber (or feel warm if blind). The scroll is identified only if at least one thing went from known-cursed to known-uncursed.

aosdict, scorchgeek

Artifact flail or short sword, the Debugger. Deals double damage to all a-class, s-class, and x-class monsters.

aosdict, raisse

When multiple-turn searching, stop when a new monster enters your field of vision.

stenno

Random closets that have secret doors (but not no door at all) can sometimes generate a random item inside, or possibly a dungeon feature like a sink.

aosdict, greqrg

Unchanging prevents you from starting to turn to stone (it already prevents starting to turn to slime), and if you are in the process of turning to either, it halts the process but does not cure it.

greqrg

After a priest gives you two bits for an ale a certain number of times, they say "wow maybe I should not enable your alcohol addiction" and stop giving you more.

attie

Custom-order shop: you pay up front for an item which is not there, and come back a certain (random maybe?) amount of turns later, when a mail daemon will deliver the item.

attie, aosdict

You can dual wield Sting and Orcrist; this gives an even bigger damage bonus against orcish monsters.

K2

You can ascend while already on Charon's boat.

attie

Fruit juice turns into booze all on its own if you leave it alone for long enough.

raisse

Unihornless conduct.

PeterQ

When a controlled teleport kicks in while you're traveling, the cursor auto-selects the spot you were traveling to.

raisse

Special candle found generated in Gehennom. While one is lit on a level, it suppresses spawn rates and makes the difficulty about what it is now (without the candle lit it is much harder). They should be fairly nonrenewable, perhaps wishable but not polymorphable. This limits your duration of time in "easy Gehennom" before it gets harder. The candles work the same outside Gehennom, but are less useful (maybe they specifically suppress demon spawns).

ais523, jilles, eraserhead

Various forms of AoE monster-debuff candles. Charm them, anti-undead, et cetera.

eraserhead

Let the player type "bgf" at a wish prompt and alias it to "blessed greased fixed".

PavelB

Entering '*' at the prompt for genocide does a this-level genocide attempt of all creatures. Cursed reverse genocides random monsters, blessed kills all monsters level-wide subject to a resistance roll, and uncursed does the same but in a smaller radius.

ShivanHunter

You can haggle with shopkeepers to sell items. They'll make an initial lowball offer, you can counter with something, they can counter it, eventually converging to a mutually agreed price. Sometimes refusing to go lower can convince the shopkeeper to accept the higher price; sometimes the shopkeeper will refuse to go higher. If you make an offer _lower_ than their current offer, give them a YAFM '[shk] raises his/her eyebrow. "Deal."'

catnameddrew, aosdict

Dropping a lit candle on a (coaligned?) altar gives you a message giving a clue to your alignment (and/or god anger, luck, etc), by flaring up or flickering or going out or whatever.

unknown

Remove fainting and direct starvation as a game mechanic.
In its place, just permanently and repeatedly decrement the hero's Strength or Constitution while they are in the Starving range (when nutrition &lt;= 0) until the hero dies from stat loss.
The reduction happens when you hit -N nutrition, and it gets reset to 0 when this happens.
Permanent reduction is done by reducing the current and highest-reached values of the stat by 1, so restore ability won't restore its full previous value.
Since Fainting was pretty lethal already, the interval between losing points should be pretty short.
When you eat something, before adding the nutrition from the food, your nutrition resets to 0.
Sustain ability prevents stat loss but makes you faint instead.

vivit, aosdict

Factor spell school and role (and presumably your role's skill cap in that school) into spell success rates.

lorimer

Allow spells to be moved to arbitrary letters, not just the letters the player currently knows.

ChrisE

Pressing space gives the YAFM "This command intentionally left blank."

Camwin

If the player has glowy confuse-monster hands, ranged projectile attacks also work to confuse monsters, not just melee attacks.

Chris_ANG

Confuse monster scrolls grant more charges than castings of the spell do. This means that the uncursed scroll should grant several charges, and the blessed one even more.

Chris_ANG

Reduce the level of create familiar significantly, and make it only able to create replacement pets and possibly similar low-difficulty monsters, and not work if you already have any pets. Add a 7th-level clerical spell, "create minion", that summons tame/allied minions of your god.

Chris_ANG, NeroOneTrueKing

Invoking the Amulet of Yendor gives you a random possibly helpful, possibly harmful effect:
Temporary intrinsic regeneration.
Recover 5d10 Pw for free.
Paralyze all adjacent monsters for several turns.
Paralyze you for several turns, bypassing free action.
Teleport.
Shuffle blesses and curses on your inventory items.

aosdict, hothraxxa

A compass item, which when invoked points up or down depending on where the stairs to Vlad's Tower are. It spins around if you're on the level itself or inside the tower.

eraserhead

When you forget a spell, give the player a message "You have forgotten the 'foo' spell." Also give warnings when you reach 10% and 1% memory.

aosdict, AmyBSOD

A spell or intrinsic that negates the single next instance of HP loss, and then goes away.

PavelB

When you have greasy fingers, you can touch and pick up cockatrice corpses safely.

nooodle, aosdict

Allow capital letters to be entered at direction prompts.

nooodle

Fountains can be contaminated by letting corpses rot on top of them. This makes them more dangerous to use.

K2

Electric spider that, when it stands on a web, can electrify that web and all contiguous ones, dealing shock damage to anything in it.

FIQ

Make rings not explode from shock damage. Only wands can explode.

FIQ

An early-game body armor piece that increases Pw regeneration.

FIQ

Negative "paranoia" intrinsic that randomly adds and removes Is from the map.

Muad, aosdict

The portal on the Plane of Fire moves around, one space in a random direction each turn.

aosdict, ais523

Instead of the Wizard of Yendor stealing all quest artifacts, he can only steal ones that don't belong to your role, since you didn't actually earn them.

AmyBSOD

The #attributes screen tells you how long it has been since you started the game in wallclock time, for speedrun checking.

PavelB

A bunch of scattered ideas for handling candles, given that the hero almost always wants to have only one lit at a time:
Track all candles separately unless they have the exact same number of turns remaining.
Merge all candles automatically, but still keep track of each one's lifetime. (This would enable lighting multiple candles and then having one of the stack burn out.) When you light part but not all of a stack, the game internally picks the shortest candles.
When candles merge, their lifetimes are averaged together.
You can't light more than one candle at once at all.
When candles merge, the candle with the shortest life automatically sacrifices as much of its lifetime as needed to "top up" the rest of the stack. That is, if the lifetime is 400, a candle with 50 turns remaining will merge with a candle with 375 turns remaining, making a stack of 2 candles with 25 turns remaining; when those 25 turns are up, it becomes a stack of 1 candle with 400 turns remaining.

ais523, FIQ, Pinkbeast, aosdict

Allow the player to complete the Invocation as long as they have ever had 7 different candles in the game, even if they don't have any right now. Flavoring this as the candle stubs being kept around and sputtering to life for long enough to do the invocation, immediately snuffing them afterward.

Pinkbeast

While wielding a polearm, moving orthogonally towards an enemy that is 3 spaces away (making it 2 spaces away, after the move) makes a free attack on that monster.

ais523

Weapon differentiation - possibly a replacement of the old D&amp;D "damage vs. small / damage vs. large" system currently in use. Weapons would do the same damage regardless of what size the target is, but might get a damage bonus or penalty based on if the target is vulnerable or resistant to piercing, slashing, or whacking/blunt weapons. Being resistant to this weapon type means that the damage is halved; being vulnerable to it means that the damage is multiplied by 1.5. Some obvious examples:
Most undead are resistant to piercing damage. Skeletons are additionally vulnerable to blunt damage.
Thick-hided animals are resistant to slashing damage.
"Blunt is best against hard things, slashing is best against soft things, piercing is best against fleshy things"

aosdict, FIQ, ais523

Whenever a lich is created, a special phylactery amulet is created somewhere on the level. When the lich is killed, the phylactery begins a timer to resurrect into the lich again. The player can somehow destroy it to finish the lich off once and for all.

FIQ, ais523

Give potions more side dipping effects:
Dipping an eroded item in a healing potion repairs erosion on it; 1 level for regular healing, 2 for extra healing, and 3 for full healing. Restore ability will repair all erosion as well.
Dipping a negatively enchanted item in a restore ability potion reverts it to +0 if the potion is blessed, adds 1 point if uncursed, and does nothing if cursed.
Dipping an enchantable item in a gain ability potion enchants it (by 1 point, always).

aosdict, Demo, Homage

If you have very high strength, kicking open a door can cause it to be knocked off the hinges and land on top of a monster behind it.

PavelB

A spell that lets you mark a tile within some radius. A few turns later, any monster on that tile is dealt significant damage.

PavelB

Chargeable ring that reduces incoming damage but may lose a charge every time you take damage.

PavelB

Sunsword does extra damage to vampires and trolls, on top of its normal bonuses versus undead.

FIQ, jonadab

The travel command automatically opens doors as you go.

Luxidream

Using wizard lock on a monster locks their pack, preventing them from using items against you.

Chris_ANG

New object property "sacrificial". When something bad happens to you (take any one bad effect, really), if you have a sacrificial object equipped, the object disintegrates and the effect is nullified.

FIQHack

aosdict

Replace the mysterious force with "dark energy", which starts pooling from the high altar of Moloch soon after you get the Amulet, and thereafter from the downstairs of a given level. If you are caught by the dark energy, you start taking a bunch of damage, limiting the amount of time you can spend on levels after getting the Amulet.

PavelB

Anti-magic fields end a bunch of temporary magical intrinsics, such as speed or see invisible.

nooodle

Cursed scrolls of wishing give the usual cursed wish effect - the item comes out cursed regardless of beatitude, wishing for positives gives you negatives, etc.

Fourk

FIQ

Add stunning and confusion spheres, which cause those effects when they explode.

stenno

Add spheres that give buff effects and deal no damage to whatever they explode at. They target tame monsters if tame, and hostile monsters if hostile. There is a spell that summons them.

FIQ

Artifact weapon that creates a shockwave upon hitting a monster, dealing minimal damage to other monsters behind it.

PavelB

A role whose main mechanic is engraving and carving different magical runes on the ground.

carlarc

A key that you can prefix some action with to voluntarily make that interruptible action uninterruptible.

Luxidream

Monks get a small amount of free bonus movement points when they kill a monster bare-handed, and also gain a small amount of free bonus movement points while making movement actions and not wearing body armor.

Luxidream, ais523

When you kill a demon lord, its lair becomes diggable.

bouquet

You can eat cloaks of protection and invisibility to get those intrinsically. Eating a cloak of protection is equivalent to eating a +3 ring of protection.

aosdict, Tone

If you use any stolen shop items while in the shop, the shopkeeper recognizes them and gets angry at you.

NAOrsa

The mysterious force triggers every certain amount of turns; this sends you either back to the downstairs of your current level or the upstairs of the level below. Changing levels resets the timer.

ais523

Stepping on a squeaky board near a sink may spawn one or more sewer rats on the sink. Alternatively, sinks may occasionally just spawn a sewer rat on their own.

Chris_ANG, aosdict

When a spellbook's ward is studied, it is possible to get a non-failure, non-success result of "you're not skilled enough to tell if there is a useful ward here". This is done by throwing the player's Int, XL, and possibly other stats into some deterministic function along with the book's object id and the ward it actually contains.

dNetHack

aosdict

Gauntlets of force guarantee that any #force attempt will succeed, and will not break your weapon or items in the container being forced.

SporkHack

aosdict, carlarc

Rather than making weapons train 1-to-1 on all successful hits, make them train differently:
Weapons train only when their natural damage die rolls a 1 (ignoring other weapon damage bonuses), so that weaker weapons train faster than stronger ones, and weapon skill for stronger weapons comes in later in the game rather than having all players reach Expert relatively early in the game. This has the oddity of incentivizing orcish weapons over regular, elven or dwarvish though.
Make the enchantment of your weapon irrelevant to training or even make training slower with a positively enchanted weapon; if the weapon has magical homing assist technology, you're not really building skill in how to use it that much.

aosdict, ais523, Luxidream, Pinkbeast

Allow the game administrator to put a random value that will be mixed into the game's seed into the sysconf file, so that RNG-predicting manipulation can't be used.

jonadab

A #ragequit command, that quits the game without any confirmation. But it's a non-autocompleting extended command, so you do have to type the whole word out.

aosdict, AmyBSOD

Blessed gloves of any type allow you to handle cursed weapons without them welding to your hands.

carlarc

Artifact wand of striking whose damage increases with its recharge count. Its odds of exploding on a recharge are lower than usual for wands.

PavelB

Artifact blank spellbook that guarantees success when writing in it and can be read infinitely without blanking. However, it can never be blanked or cancelled. Or possibly it generates as a random type of spellbook, and can only be blanked if not yet read.

Tone

Crystal balls can accept words instead of symbols, such as "dragon" or "trap".

carlarc

Rope golems drop leashes and bullwhips upon death.

carlarc, PavelB

Dipping potions deliberately into water turns them into water in one go, without a need to dip twice. You get a message about pouring out the old potion and filling the bottle with water.

Luxidream

Nerf the effects of diluted potions in order to disincentivize diluting them and fix alchemy abuses. Start with healing potions: a diluted healing potion of any type heals only half as much as otherwise, and either confers half as much max HP as an undiluted potion or possibly no max HP at all. When alchemizing with diluted potions, half of the amount dipped will bubble or steam off as water, wasting those potions entirely (e.g. 6 diluted healings + gain energy = 3 diluted extra healings).

Pinkbeast, aosdict

You can dip a potion into a sink to pour water into it from the tap, diluting it and causing runoff which subjects you to vapor effects (hopefully identifying it).

Tone, aosdict

Unless you are blind, all boxes are obviously locked or unlocked once you see them. There is no need to first loot a chest only to learn that it's locked.

Luxidream

When you're hallucinating, show the Black Market as "Sam's Club".

UnNetHack

Luxidream

If you dip for Excalibur while using a helm of opposite alignment to be lawful and the attempt would succeed, the Lady of the Lake notices that something is wrong. She emerges from the fountain, grabs your sword, turns it into Excalibur, and rips off your helmet. This allows non-lawfuls to get Excalibur, but only by defeating her.

aosdict, carlarc

New artifact Imaginary Widget: Random non-polearm weapon type. Deals double damage to monsters that don't exist in real life (e.g. foxes and mastodons and giant eels are real; wargs and mumaks and krakens are not).

Luxidream

When a packrat generates normally, a random item is created that it carries.

SpliceHack

aosdict

Blessed harmful potions give resistance to that effect.

carlarc

When choosing the monster type for a mask, use a higher difficulty threshold than it would take to generate monsters; otherwise masks only generate with level-appropriate monsters which the player probably doesn't want to turn into.

SpliceHack

aosdict

When viewing skills with #enhance, show the maximum skill caps for all listed skills.

Luxidream

In cases where Vorpal Blade won't decapitate because the monster is headless, it does double damage instead with the message "Vorpal Blade goes snicker-snack on the foo!"

carlarc

Make the Castle a side branch, putting two down staircases on Medusa, one of which goes to the Valley and the other of which goes to the Castle branch, first preceded by several maze levels.

jonadab

If the Wizard has started to harass you, enlightenment shows "You are being harassed."

carlarc

If Mjollnir is thrown and would hit a valkyrie player monster wearing gauntlets of power, they catch it instead.

Luxidream

Remove the possibility of "Blecch! Rotten food!" from uncursed non-corpse comestibles.

Luxidream

Scale the monster "healing" spell so that late-game spellcasters can actually heal themselves with it.

AmyBSOD

Orcish characters will never be able to tame elves, and vice versa.

Luxidream

Barbarians and cavemen get weapons/ammo instead of spellbooks as a prayer boon.

carlarc

Falconer role that starts with a kestrel and special arm-protecting gloves.

jonadab

Track monsters that you have named. If you genocide a class of monsters that contains any you have named, notify the player of their death.

Luxidream

Giantslayer kills all insects adjacent to the player for a possible "Seven at one blow" effect.

Luxidream

Izchak sells scrolls and wands of light, maybe spellbooks too, at low frequencies.

raisse, aosdict

God gifts come pre-identified: artifacts automatically become known (so that you get "the Giantslayer" rather than "a long sword named Giantslayer"; non-artifacts automatically become type-identified.

carlarc

The scroll and spellbook of web allow you to fire a web projectile or beam in a direction. If it hits a wall, it creates a web on the space before it; if it hits a monster it creates a web on the monster's space and immediately entangles it. If it goes far enough without hitting anything, it creates a web at the end of its range.

SpliceHack

aosdict

Psuedodragons that are tiny D-class monsters. They may be the starting pet of Wizards, but don't grow up. Instead, they have some kind of telepathic/psychic/magic-enhancing passive ability that scales with their level.

aosdict, K2

Explosions destroy diggable walls.

PavelB

You can knock monsters into water or lava with a staggering blow.

karlos

The "To what level do you want to teleport?" prompt accepts level names defined by the player.

ChrisE

Add a menu option for transferring items from one container to another (in inventory or on the ground).

Ashpool

Add "reach the Valley of the Dead carrying the Amulet" (or the Castle) as an achievement tracked by the game.

stenno

Centaurs can use lances as if they were riding.

stenno

Elven daggers and arrows (and really any pointy wooden weapon) has a 5% chance of instakilling any vampire who is not wearing body armor.

Homage, aosdict

If you attack a peaceful monster in sight of your quest guardians and leader, they give you a warning rather than instantly becoming angered.

Homage, aosdict

Digging through a vault wall counts as 5 tiles (for digging time or wand of digging purposes, and dulls your digging tool's enchantment by 3.

jonadab

Dungeon branches that are completely submerged: their levels have a special level flag that treats you as underwater no matter what the terrain is. Would work better if a breath timer were implemented rather than instant drowning if a magical breathing source is lost. Trying to go down the stairs leading into the branch without the ability to survive underwater is equivalent to jumping into a pool: you will get wet and then crawl out (still on the stairs), without changing levels.

AmyBSOD, aosdict

Karma stone: a type of gray stone that, if it is blessed or cursed, can be rubbed on another item to transfer the blessing or curse to that item, making the stone uncursed in the process. Cursed karma stones in inventory eventually transfer their curse to a random item on their own; the stone might remain cursed after doing this. The loadstone in the Mimic of the Mines is replaced with one of these.

aosdict, Luxidream

Scroll of religious text, which can be read for a prayer (or opportunity to pray) that ignores your prayer timeout.

PavelB

Not all zombies are hostile; only the hungry ones are. Thus, some zombies might be generated peaceful. However, a nonhungry zombie has a small chance of turning hungry each turn.

GruntHack / EvilHack / Zombie Apocalypse Patch

aosdict

If an empty bag of tricks can function as a sack: don't destroy the contents when it gets recharged. Instead, just make the contents inaccessible until it becomes empty again. Also, add a possible random effect to using the bag while charged: it spits out one of its contents at random.

bhaak's bag of tricks proposal

aosdict

Boots with the random appearance of "hiking" slightly decrease the speed penalties if you are encumbered.

PavelB

Eucalyptus leaves always taste terrible, except to certain herbivorous polyforms (such as koalas and other zouthern animals in SLASH'EM).

bug_sniper

In item classes which have multiple price tiers (scrolls, spellbooks, potions, rings, etc), unidentified items will sell for the lowest price tier and cost the highest price tier.

AmyBSOD

Since polearms are designed for use against mounted enemies, they get bonuses versus all u and C monsters. Also mounted enemies, if in a variant that has monster riding.

AmyBSOD

Turn kicking a door into an occupation: you'll keep kicking it until you get interrupted somehow, or successfully kick it down.

PavelB

Holy and unholy weapon properties apply only when the weapon is respectively blessed or cursed, and the object then shows as "holy" instead of "blessed" or "unholy" instead of "cursed".

dNetHack

NeroOneTrueKing

Move Sokoban much later in the dungeon, and make time not pass there. This Sokoban would consist of larger levels, but the boulder puzzles don't cover the whole level.

ais523

Gloves that are sufficiently burnt or rotted only protect from touching cockatrice corpses some of the time.

AmyBSOD

Priest characters are allowed to choose the pantheon of gods they follow. This gives them Basic proficiency in one or two of the skills of that pantheon's corresponding role.

picaresquieu

Stomping boots. While wearing these, you may instakill and move into the square of all monsters in the a, s, and x classes.

Tangles

A bag of tricks may occasionally engulf and digest you.

K2

Shining spellbooks give off as much light as a candle when wielded.

stenno

Cancelled trolls won't rise from the dead.

jonathanhanes

Fruits can be applied to create potions of fruit juice.

jonadab, FIQ

A magic trap that causes you to yearn for your distant homeland may instantly magic portal you to your quest home level.

Hekik

Iron and copper items engulfed by gelatinous cubes get corroded in the process.

Andrio

Dropping items into a sink has a 1% chance of sucking you in and levelporting you randomly.

winny

Wishing for "world peace" pacifies all non-unique monsters on the level.

Luxidream

Procedurally generate the game-equivalent of Elbereth each game, and make it fairly likely to appear somewhere in the Dungeons of Doom.

K2, bug_sniper, Luxidream

Whenever you arrive on a level through a portal, either the portal moves a short distance or you appear a few spaces away from it. Or turn all 2-way portals into paired 1-way portals which can have different arrival coordinates defined.

ais523, PavelB

Cursed amulets of life saving allow you to remain in the game, at the cost of bringing you back as a skeleton.

Puck

Baluchitheria and other elephant-like q flee from small rodents like sewer rats.

ChrisE, aaron

Shopkeepers recognize items that they originally owned but were stolen from them by pets, etc. They reclaim ownership of those items if you return to the shop with them, or possibly get angry.

ChrisE

Shopkeepers track your petty thefts, and automatically anger if you steal a valuable single item or 50% of their stock or items totaling more than 1000 zorkmids.

opticdelusion

If you stand on a pile of objects that are all the same class, replace the "objects" in the message "There are several objects here" with the name of that class. E.g. "There are several weapons here". Also do this even more specifically if they're all the same object type: "There are several daggers here".

Elronnd

Your base hunger rate is adjusted slightly up or down based on the amount of weight you're carrying.

PavelB

Dragonbane behaves like in DCSS: it gains enchantment, safely and for free, upon killing dragons, maybe up to a higher maximum than usual.

luxidream

Some limited way to charge rings that isn't the general-purpose magical charging that also charges wands and tools. Maybe add a "scroll of enchant ring" that, like armor and weapon scrolls, only works on rings.

aosdict, ais523

The potion of levitation has negative weight, and lightens your inventory load rather than weighing it down more.

PavelB

Remove ulevel as a factor from the logic that determines how large a newly generated monster group will be. Instead, scale the group size based on depth. (And to take this further, groups created by magical means such as create monster should be independent of both factors).

aosdict, stenno

Crystal gear (wands, plate mail) occasionally comes in a certain gem type.

riker

Randomized clan names for samurai player monsters.

riker

Artifact "Shade Cloak": cloth cloak that is always tattered (has 1 level of unfixable erosion), confers (not-very-fast) speed and drain resistance. Invoke effect is temporary phasing and the incorporeality of a shade.

NeroOneTrueKing

Random amulet appearance "necklace", which apart from its regular amulet effect boosts Charisma when worn.

riker

You can douse an angry shopkeeper in Lethe water to make him forget you.

Lethe patch

jonadab

Alter the player's corpse weight based on how hungry they were when they died.

Luxidream

If the player drops a leash that's in use or gets teleported away or dies, etc, the pet starts dragging the leash like a player drags an iron chain.

jonadab

Sand terrain, which slows you down a bit when you walk on it. Shows up in certain special levels. Might be a . glyph.

Chris_ANG

You can apply a towel to remove grease from items if your face and hands are already clean when you apply it.

NeroOneTrueKing

Metroid nest: a 1-level branch appearing in 1/8 of games. Contains hostile metroids and a metroid queen. It contains some futuretech gear as a reward.

dNetHack

Tarmunora

A light source that only gives off radius 2 light, but lasts longer, for races with low-light vision.

dNetHack

riker

Instakill effects deal a large amount of HP damage rather than instakilling, and give an appropriate message when something survives them.

NeroOneTrueKing

Pudding globs that fall onto a sink slide down the drain and disappear.

valkyroo

Separate command to pick up an item and put it into a bag immediately after, in 1 turn. Or an option that changes pickup behavior to this effect.

AmyBSOD

Allow multiple randomized item descriptions to correspond to the same actual item identity (e.g. a yellow potion and a red potion might both be healing).

ais523

Healers receive an alignment penalty from using poisoned weapons.

riker

A troll killed by fiery or acidic means (including Fire Brand) cannot revive.

riker

Add Acid Brand and Storm Brand artifacts. Ideally make these all different base weapon types.

riker

When you get lifesaved, a ghost with your name may be created next to you.

riker

Don't maybe give Wizards a scroll of punishment in their initial inventory.

Andrio

Make zruties eat every sort of food off the ground, including tainted corpses but not cockatrice corpses. Make them MZ_GIGANTIC and block line-of-sight. Give them a bull-rush attack that runs you over like a boulder trap but with more damage.

ShivanHunter

Magical sources of light that light up a fixed area are temporary, and revert to darkness given time.

AmyBSOD

Being engulfed by a solid monster makes you blind unless you are carrying a light source, because it's dark in their stomach.

AmyBSOD

Save the exact text of wishes made, and add it to either the dumplog or the #conduct list of wishes.

ShivanHunter

Equipment or artifact set bonuses, such that carrying or equipping all of them provides some bonus effect.

bug_sniper

Player status called Terrified: it acts like confusion and stunning in that it makes you move in uncontrolled ways, except that it pathfinds away from whatever is scaring you.

Hekik

When you are traveling with _ and controlled teleportitis activates, automatically select the place you were traveling to, or place the cursor on that spot and wait to confirm. Add an option to toggle this behavior.

Ashpool

Various ideas to give the bonus from certain sources of speed only as a bonus to movement, not to getting more turns to attack, use items, etc.
First, to classify: most agree that speed boots, intrinsic speed, and steed speed should be sources that only give extra movement opportunities, while polyform speed should give extra full turns. Less agreement on magical sources of very fast speed (the potion and haste self), but general opinion seems to be that these should also not be limited to movement.
Add a second pool of movement points that coexists with regular movement points, but can be used ONLY for moving. Speed boots and its fellow sources add to this pool, and any unused points in it are discarded at the end of the player's turn. When you make a movement, points are deducted from this pool before being deducted from the "core" pool. Note that this approach can cause core points to accumulate to the point where the player can eventually get multiple non-movement actions on their turn.
Reduce the movement point cost if you are taking a movement action and have sources of movement-only speed. (This might interact oddly if general-purpose sources of speed continue to add movement points as usual.)

NeroOneTrueKing, aosdict, Tarmunora

Yellow dragons digest the player much faster than the other types of dragon, because they're all acidic.

dragon-engulfing variants

aosdict

Thirsty weapons sometimes gain a point of enchantment when they drain a level from something.

object properties

aosdict

If you attack a peaceful monster, other peaceful monsters that saw the act but grudge the first monster will not be angered.

Grudge Patch

aosdict

Shopkeeepers can summon a minion or clone to guard any second door into their shop if one should happen to exist.

hothraxxa

Premonition system: under various conditions (crystal balls, clairvoyance, dreaming while you sleep, the Oracle) you can receive a premonition of something that will appear later in your game (this could be almost anything: a monster, object, dungeon feature, special room, etc) which then has a very high chance to generate subsequently.

aosdict, AntiGulp

Bringing back different types of keys for different sorts of locks. This is not the old random key shapes and random lock shapes system; the discussion concluded that special keys should be used for a few specific purposes: game progression, a one time use reward, or some non-unique type of door where each key is one-time use or limited use. In particular, this third one could be used in Gehennom to block off areas, with "soul keys" or something similar that open special doors there and are generated with demons. Gehennom doors could also involve a blood ritual requiring some sort of expenditure of resources or damage to the player.

NeroOneTrueKing, aosdict

Implement directional #loot for objects embedded in a wall where the object is a spellbook and the room type is LIBRARY.

dNetHack

aosdict

All spheres should explode in a 3x3 radius like gas spores do.

Tone

Dexterity save against falling into a pit or hole (rather than the usual flat 20% chance for traps).

Luxidream

Make it possible to leave bones on certain levels that have a branch entrance in them (mainly mine entrance, sokoban entrance, quest), by virtue of removing the branch entrance before saving it as bones. If branch upstairs are removed in this manner, replace it with a pile of rocks; if downstairs are removed in this manner, replace them with a pit.

jonadab, aosdict

A levelable haggling skill that gets you better prices in shops.

K2

Make all unidentified objects of the same object class cost the same (rather high) amount until you know what it is, at which point it can be bought and sold for its correct price.

Tone

Monster generation in the Quest treats your level as the maximum of your actual level and the minimum level required to receive the Quest.

Andrio

Give Sunsword an invoke effect that creates permanent light in a radius like the wand of light. "PRAISE THE SUN" optional.

aosdict, AntiVirus

Make orcish armor out of bone rather than iron.

jonadab

Regenerating HP naturally doubles your hunger rate while you are regenerating.

Chris_ANG

Lightning spells:
Lightning bolt can be a melee range spell that deals heavy damage. (Most suggestions for a lightning bolt spell involve a simple ray though.)
Chain lightning is a spell that forks off and hits adjacent targets in a breadth-first search (see here for how it  might work). Possibly, the lightning bolts can only chain off at 135 or 180 degree angles (maybe 90, too).
Lightning storm, which causes an electrical explosion centered on every monster in your line of sight (possibly with a decreasing chance of doing so as it gets further from you).

NeroOneTrueKing, Chris_ANG, rikersan, aosdict, Demo

Reading mail does not break illiterate conduct.

bug_sniper

"Homing" object property, which generates on ammo and guarantees a hit.

object properties

aosdict

Bats flee upstairs whenever possible in Gehennom, because they are bats outta hell.

Luxidream

You scuff engravings less when wearing elven boots because you are walking very quietly.

rikersan

Tame dragons never drop scales.

hothraxxa

Pool of acid terrain that deals severe damage if you fall in.

K2

Partial intrinsic teleportitis works as regular teleportitis except you teleport less frequently. (When a teleport would trigger, roll your percentage; if the roll fails, nothing happens.)

Partial intrinsics (SporkHack, EvilHack)

aosdict

Tinning huge corpses produces the tin as usual, but just makes the corpse partially eaten instead of destroying it.

bug_sniper

Randomly generated foocubi may generate with some amount of gold (taken from previous partners).

Andrio

If a cloak is on top of an item pile, it will protect anything underneath it from burning up in a fire blast on that space (though the cloak itself might burn).

riker

Monsters will grudge another monster wielding an artifact that is a bane of them.

Grudge Patch

alex__

Shopkeepers of stores besides general stores will identify any item that can be sold by their shop for a fixed price. General store shopkeepers either don't identify anything, or can identify everything for you with an exponentially increasing price.

Shopkeeper ID services

aosdict

Remove the special damage bonus skill tables for bare-handed and martial arts combat. In place of them, scale up the die size based on skill: bare hands damage is a d2 at unskilled, a d3 at basic, etc. and martial arts doubles this die size, for a d4 at unskilled, a d6 at basic, and so on up to a d14 at grand master. Note that this still gives pretty poor damage output. Possibly it should be 2 dice being rolled (with the die size changing as described here).

rikersan

Give the Magic Mirror of Merlin an invoke effect of enlightenment.

rikersan, aosdict

Rename mattocks to 'cutter mattock' and pick-axe to 'pick' to make them less ambiguous.

rikersan

Rust monsters are only hostile towards you if you are wearing or carrying iron or are an iron golem.

rikersan

Underline statues to distinguish them from white colored monsters.

bhaak

Moving right into an engulfer with the 'm' prefix automatically engulfs you.

Andrio

Invoking artifacts for invisibility makes you visible again if you are already permanently invisible. Also, move the Orb of Detection's invoke invisibility ability to some lesser artifact because it's a lame power for a quest artifact.

raisse, aosdict

Candles and lamps "burn brightly" when blessed and just "start burning"/"is now on" when uncursed. Lanterns don't change their messages.

rikersan

To make zombies more bearable than giving you immediate deathly illness or brain drain, do it like D&amp;D where they need to grapple you before biting you. Do this by giving them a sticky grab attack, and ignoring the existence of their bite attack if they aren't already grappled on to you.

GruntHack, EvilHack

aosdict

Adjust NetHack's monster speed system to accommodate the additional property that if your speed is greater than a monster's, it is impossible for that monster to move 2 turns in a row before you get to act.

Homage

Restrict bones files from being loaded (possibly just discarding the bones file) if they contain monsters that are far out of difficulty for the player encountering them.

ChrisE

Deafness should provide total protection against cockatrices' hissing attacks.

jonadab

Deafness multiplies your spell failure rate by a constant amount, due to maybe not getting the pronunciation right because you can't hear yourself.

PavelB

Define a new set of ability score maximums which represents the highest the score can reach via exercise. These caps are always equal to or higher than the existing maximums, which represent the highest a stat can be increased to through potions of gain ability or other stat-boosting effects. In some cases, the exercise maximum should stay the same and the non-exercise maximum may need to be decreased.

aosdict, Chris_ANG

Monster spell (or song, for bard-patch variants) that temporarily causes allies to grow up by one growth stage, regardless of its level (e.g. a little dog under this effect will become a dog, a demilich will become a master lich).

rikersan

A mechanism for checking the health of your steed that isn't as specialized as a stethoscope. Possibly #chatting downward at it gives you a clue.

AntiVirus, aosdict

Aggravate monster, as well as possibly wielding Stormbringer, disables Elbereth's protection.

FIQ

Frisbees, a plastic weapon using boomerang skill. Deals only 1d2 damage, but can fly in a straight line at extremely long range. Frisbees thrown at dogs might tame them.

rikersan

Magical or enchanted boomerangs can gather items from the floor and return them to you.

AntiGulp

Artifact unaligned touchstone called Grinder: rubbing it on or applying it to an object repairs one level of rust or corrosion but decreases enchantment by 1 (which can go negative). Invoking it cancels a single object.

rikersan

When you are turning to slime, higher luck increases the odds of a container trap or magic trap being a tower of flame, and increases rather than decreases the odds of any tower of flame trap (container, magic and fire) hitting you.

ais523, aosdict

Make it impossible to portal-dance in Fort Ludios and beat it easily by putting a second exit portal in the fort and some sort of one-way gate in the starting room which has no other exits and the original exit portal.

FIQ

Different death texts for if the quest nemesis is paralyzed or sleeping when they die.

rikersan

Pets eat corpses incrementally, not all at once, and you can interrupt their eating by moving them off the corpse (e.g. swapping places). The corpse becomes progressively partly eaten as they eat it. Interrupting their eating deducts tameness points from them equal to how many they would have gained if they had been allowed to finish eating normally.

vivit

Elven characters can read the runes on runed objects (which presumably don't say much of interest, except possibly a runed wand will say what it is).

vivit, aosdict

Refactor to-hit mechanics into a simple 1d(attacker's bonuses) versus 1d(defender's bonuses) computation, where the attacker hits if their roll is higher.

Pinkbeast

Anyone who wields Sunsword can perform the #turn command, which is flavored as brandishing the sword threateningly.

rikersan

Archeologists can ascertain a rough estimate of an item's sale value without a shop handy, due to their profession.

FIQ

You can enter into a pact with a single non-unique demon of your choice over the course of a game. This gives you significant benefits (varying and according to the type of demon) but also major disadvantages for the rest of the game. One major disadvantage for all demons is that it becomes much harder to be in good standing with your god. Two other examples of advantage/disadvantage pairings: a +8 damage bonus in exchange for being unable to become fast or very fast, being able to cast any non-healing spell in the game in exchange for no natural heath regeneration.

FIQ

Illithids and illithid-race players can only eat brains and corpses that have brains. If you kill a monster after eating its brain, its corpse offers no nutrition.

EvilHack

aosdict

Striped shirts have random per-shirt prisoner numbers on them when you read them.

Convict patch

aosdict

Covetous warpers can only warp to the location of the item they covet. This means that if you are carrying it, they can warp to you all they want, but they can't warp back and forth to the stairs.

FIQ

Markers no longer have charges; instead they drain Intelligence points.

FIQ

Cartomancers start with the create monster card identified and they have a whole bunch of them containing various early to mid game monsters in starting inventory.

SpliceHack

aosdict

Whenever the Wizard of Yendor revives, he has immunity to whatever he was killed with the last time.

ais523

Color priests differently to distinguish them from player monsters.

Tone

Arrows fired from The Longbow of Diana will never break and will automatically return to you. It also counts as your racial bow regardless of your race.

FIQ

A "blank ring", which has no powers. A gemstone can be inserted into it, which will turn it into that type of gemstone ring, whatever it happens to be. Possibly can be obtained by canceling other rings.

FIQ, aosdict, jonathanhanes

Challenge mode in which all non-sessile monsters are faster.

ais523

Every time you use a unicorn horn to cure a problem, the chances of any unicorn horn curing that problem in the future slightly and permanently decrease.

ais523

Damage reduction from AC happens before half physical damage instead of afterward.

ais523

An option to #terrain that shows spaces you have stepped on. (There is also popular demand for a NetHack4-like display of this on the regular map.)

aosdict, BEHiker91W, luxidream, Tone

Add a TDTTOE message about swinging your dead cat if you start hitting things with a wielded cat corpse. Also have a separate message "There isn't enough room to swing your dead cat" if there are 4 or more walls adjacent to you.

aosdict, bubbles

Oilskin cloaks prevent you from getting entangled in webs. Greased cloaks do too, but the grease may wear off in the process.

rikersan

In certain cases, you can see what telepathic monsters can see in a radius of 2 or 3 centered on the monster, assuming it fails a saving throw versus you reading its mind.

K2, aosdict, jonadab

A spell that creates a tame speed 0 monster that gives you permanent vision in a radius around it. Level 5 or 6 divination spell.

aosdict, K2

In an effort to make unicorn horns not infinitely useful but also preserve their other good qualities: Split the unicorn horn into two items, the horn, a simple tool which now has a number of charges, and a "unicorn spear" / "hardened unicorn horn" which is a weapon. Both items have the same base damage, are two-handed, and use the unicorn horn skill, but reading a scroll of enchant weapon while wielding a unicorn horn will transform it into the weapon version like how crysknives work. The weapon cannot be used to cure ailments.

aosdict, Luxidream, Tone, Umby

Cursed weapons deal bonus damage to all angelic beings.

carlarc

Improvements to secret doors:
When the player discovers a secret door, monsters still don't know about it unless they see it open.
Monsters know about some secret doors in their native area, and will use them. If the player sees a monster using a secret door, it becomes unhidden. The proposed implementation for this is to have some monster types (the Wizard, angels, etc) have full knowledge of all secret doors everywhere, and all other monsters have a bit that represents whether they know about secret doors, which sometimes gets set when they are generated and always gets set when they see some other monster use a secret door.
There are fewer or no hidden doors between the upstairs and downstairs on a Dungeons of Doom level.
Less of a Dungeons of Doom level's loot appears on a direct or near-direct path between staircases, and more of the loot appears in rooms hidden behind secret doors.
Remove secret passages from the game; they don't add much of relevance and it's harder to find ways to make them relevant.

jonadab

Any comestibles death-dropped by an F monster are rotten when eaten.

Umby

True pacifist conduct, which prohibits you from directly hurting any monster.

AmyBSOD

Booze reduces your memory retention of spells.

Demo

If a mind flayer eats your brains while you are confused, it becomes confused.

alex, jonadab

When a Priest is gifted an artifact weapon, they are unrestricted in its skill up to Skilled.

rikersan

Invoking the Longbow of Diana gives a temporary buff of "piercing", in which all your projectiles (not only those fired from the bow) pierce through monsters and continue flying.

FIQ

"Piercing" object property, eligible on ammunition, which makes them not stop flying or break when they hit a monster, continuing on to possibly hit more monsters behind it.

object properties

aosdict, FIQ

Monks can gain intrinsic immunity to just about everything by leveling up, but most of these are nullified if the monk is wearing body armor.

FIQ

Fuzz the base prices of objects at the start of every game, between 75% and 125% of the item's defined base price.

FIQ, aosdict

Use a miniature cellular automaton to determine which spaces in a swamp room will become water, rather than using a fixed checkerboard. This may not work well for tiny rooms, so enforce a minimum size constraint on what can become a swamp room if necessary.

aosdict, AntiGulp

Merge magic cancellation and monster magic resistance into a single stat "magical protection" which determines how easy it is for the magical portion of attacks to reach you and deal effects. All races have a low innate MP, but armor can raise it higher. Most monsters' innate MP resembles their current monster magic resistance.

FIQ

A set of options (similar in structure to the paranoid options) that manages triggers that you want to interrupt you. Examples of triggers: a monster attacks, you teleport due to teleportitis, a monster comes within sight, a monster comes adjacent to you.

Tone

Shopkeepers should pay you a small fee for killing a mimic that was generated in their shop. (Or at least give you the corpse for free).

bubbles

Spellbook of probing, in the divination school, that works like the wand but only works at touch range. Zapping it at yourself at skilled grants enlightenment.

rikersan

Merge the wand of enlightenment into the wand of probing: probing gives enlightenment when zapped at yourself.

rikersan, aosdict

Crystal plate mail is so transparent to magic that it provides no magic cancellation and can't be enchanted, disenchanted, canceled, destroyed with destroy armor, or cursed with curse items. Possibly extend this to any armor made out of crystal (GEMSTONE). Also possibly it always generates as +0, because anything otherwise would imply that it had been enchanted previously.

EvilHack, object materials

K2, aosdict

Unicorns of different colors grudge each other.

aosdict, Andrio

Object property "curing": allows the item to be used like a unicorn horn to cure ailments.

bubbles, rikersan

Fix the problem with Aleaxes creating a copy set of your gear which can then be used as polyfodder by flagging the armor that gets generated with an Aleax to polymorph only into non-magical items.

UnNetHack

aosdict

After you struggle free of a bear trap, it becomes disarmed.

Porkman

Dragon scale mail changes the color your character renders as depending on the color of the mail.

jonathanhanes

Excalibur starts out much weaker than it currently does, but you can perform further feats to enhance its power and give it more abilities as the game progresses. Such feats include: slaying a dragon, returning to King Arthur having finished the Quest, getting crowned as a lawful, re-dipping it into a fountain at a high experience level.

aosdict, rikersan

When hallucinating, replace "You hear a chugging sound" with either "You hear a steam locomotive passing by" or "You hear someone chant 'Chug, chug, chug!'"

Homage, aosdict

A weapon that occasionally polymorphs the monsters it hits.

raisse

Gelatinous cubes automatically engulf items thrown at them rather than the items falling to the floor.

Andrio

Foocubi gain a level when you get a negative result from them. This should perhaps be extended to other types of enemies with draining powers.

Andrio, aosdict

Hallucinatory message for squeaky boards: "You hear a chicken squawk a B note loudly."

aosdict, jonathanhanes

Cold rays are colored light blue, to be distinct from lightning.

Andrio

Dwarves don't tunnel within town limits (they can dig up the outer areas of the level just fine).

jonathanhanes, aosdict

You can use stethoscopes (or possibly probing) on eggs to identify them.

jonathanhanes, aosdict

You can somehow weaponize globs of green slime to forcibly transform other monsters into slime. Possibly this could be as simple as throwing or flinging the globs at them, perhaps subject to a monster magic resistance check for the transformation to work.

aosdict, Umby

Additional priest spells: raise undead, floor to lava, ball lightning (not a ray and thus not reflectable), summon elemental.

jonadab

Allow configuration of a list of monsters that the player should be prompted to confirm fighting before automatically attacking. Fighting with F bypasses this check.

Tone

Possibly with an option, disable auto-attacking by walking into a hostile monster; this will instead ask to confirm attacking the monster. The standard key for fighting monsters is F.

jonadab

When a monster disappears by becoming invisible, place an I on its square.

Luxidream

When you are quoted a price for an unidentified item, it is automatically remembered on the discoveries screen. (Not specified how this would interact with being quoted a different price by different shopkeepers, or being quoted both a buy and sell price for the same item.)

jonadab

Chatting with a shopkeeper makes them offer to appraise your inventory; if you accept, they will automatically type-name all your unidentified items with the price they would buy it for.

Luxidream

An artifact T-shirt that provides free action when worn, but only if no armor is worn over it.

Demo, aosdict

When either you or a creature is brought below 10% HP while wearing an amulet of life saving, it begins to glimmer.

carlarc

Add some mechanic that allows you to pay for training to unrestrict a skill and bring it to Basic. Players of any role are also able to get riding training.

NeroOneTrueKing

While you are on the ascension run, mimics prefer to disguise themselves as upstairs. It also edits your memories to make you think you remember the stair being where the mimic was.

NeroOneTrueKing, Chris_ANG

You can only use cursed potions of gain level once or twice while carrying the Amulet. After a few uses, it will start to pull you back down as you rise up, wasting the potion.

Chris_ANG

The Staff of Necromancy: a quarterstaff artifact that deals double damage to non-drain-resistant creatures (but doesn't life-drain them as the Staff of Aesculapius does), grants cold resistance and curse resistance when wielded, and can be invoked to raise one vertebrate corpse on your square as a tame skeleton.

NeroOneTrueKing

Internally mark all of your starting gear with a special flag; if you die before receiving the quest, any items marked with this flag get degraded when placed into your bones pile: things like magical armor becoming nonmagical, wands lose charges, scrolls may fade, and spellbooks are made too faint to read more than once.

NeroOneTrueKing

At the start of the game, three artifacts are selected as potential divine gifts, and you will never get any other artifact than these three by regular sacrificing. These three artifacts must not hate the player's race and ideally will provide a good balance in terms of power and utility. Gods can also grant non-artifacts as gifts, which no longer count against your odds of receiving an artifact. Also, the chance of getting an artifact is biased against low-level characters who have not made many sacrifices and towards high-level characters who have.

NeroOneTrueKing

Sustain ability also gives stun and confusion resistance, and prevents you from studying books.

Demo

Placing bag-of-holding-explosion-causing items into a bag of holding blows up the item that is trying to be placed inside, but does not harm the bag itself. If the item causing the explosion is a second bag of holding, its contents end up inside the outer bag.

jonadab

Pressure plate traps that cause all the doors of the current room to close and lock (doorways without doors could turn into iron bars or, on deep enough levels, all doors could turn into iron bars). Triggering this automatically removes the trap. Generated very rarely, and has special generation that occasionally makes it appear just inside a door to a throne room.

NeroOneTrueKing

Archeologists can apply their whips to cross over a ground-based trap with impunity, a la Indiana Jones.

Pinkbeast

Some monsters can block being detected by your telepathy, either innately (disenchanters, perhaps) or as a monster intrinsic conferred by armor (such as a tinfoil hat) or spellcasting by an ally. Also, possibly allow for area-of-effect "telepathy dead zones".

aosdict, Pinkbeast, luxidream

When you wish for an artifact and it arrives with an angry person, that person gets an appearance message, or at least a single line of dialogue.

Owned Artifacts Patch

aosdict

Zombies destroyed by turning never leave corpses, or the corpses they do leave are incapable of reviving.

Zombie Apocalypse Patch

rikersan

The cost for buying protection is based on your maximum level reached, not your current level, to prevent draining for gain.

AmyBSOD

If you have at least Basic in martial arts, you cannot injure your leg by kicking.

Luxidream

Streak mode that prevents you from having more than 1 save file at a time.

NetHack4 + variants

Luxidream

You can apply a cursed bag of holding (or possibly empty back of tricks) at a ghost to capture a ghost, which can then be used to recharge a wand of undead turning.

krm26, K2

A cursed bag of tricks can be applied at monsters to eat them up, which will add one charge to the bag.

krm26

Combine the cure sickness and cure blindness spells into one 'cure ailment' spell.

carlarc

Add several types of tape, which can be applied to mute yourself. While mute, you cannot cast spells, but you have a chance of not speaking the incantation when you read a scroll (resulting in the scroll becoming identified but not used up; none of its effects happen). There are four types of tape which randomly generate: Scotch tape (generating blessed 75% of the time and cursed 25%), packing tape (always uncursed), duct tape (50% blessed, 50% cursed), and Flex Tape (25% cursed, 75% uncursed).
Tape may fail to prevent you from reading a scroll, with a message "The magic of the scroll forces your mouth to move against the tape." followed by the normal scroll reading messages. The chance of this happening is 2% if the tape is blessed, 12% if uncursed, and 50% if cursed. When taking off blessed tape, there is a 75% chance you take it off normally, but a 25% chance that you rip it off instead, dealing 2 damage. When uncursed, there is an equal chance of taking it off, ripping it off, and having it be stuck on your face. When cursed, there's a 99% chance that it's stuck on your face, but a 1% chance that you tear it off, dealing 15 damage. Every ten turns you spend wearing tape, it might fall off on its own (5% chance), falling on the floor. Finally, every time you put on or take off tape, there is a 15% chance that it lose its stickiness, fall off if you put it on, and turn into an "odd strip of material", which can be used as a blindfold. Odd strips of material cannot be generated randomly. 

MetaNite64

A monster that gets more powerful every time an attack misses it.

jonadab

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