I'm assuming you mean the "big three" Legendary Eldrazi -- Emrakul, the Aeons Torn , Ulamog, the Infinite Gyre , and Kozilek, Butcher of Truth .
If you want any Eldrazi, like a Pathrazer of Ulamog , you can always use reanimation spells.
These three, however, have the persnickety clause:
When {card name} is put into a graveyard from anywhere, its owner shuffles his or her graveyard into his or her library.
Thus, you have to use instant-speed reanimation, cheat on costs, or hardcast them normally using obscene mana acceleration (which is basically "cheating them out" for most intents and purposes).
The proven competitive decks that do this are: Legacy " Sneak and Show ," using Show and Tell and Sneak Attack .
Modern " Tron " decks, using the power of the UrzaTron (Urza's Mine, Urza's Tower, and Urza's Power-Plant, which produce 7 mana from three lands) to hardcast Eldrazi.
Basically you use lots of cards like Sylvan Scrying , Expedition Map , or Gifts Ungiven to set up the Tron, and then go crazy with Eldrazi, Karn Liberated , and Wurmcoil Engine .
Some of these decks also run Through the Breach as a backup plan.
Before banning, Modern had " Twelvepost ," which used Cloudpost , Glimmerpost , Vesuva , like a faster and more consistent Tron.
Before banning, Modern also had " Hypergenesis ," using cascade tricks to set up a super-fast Hypergenesis .
Legacy " Elves " is an occasionally-successful but easy-to-hate deck that chains a ton of mana dorks, usually with Glimpse of Nature , to hardcast Emrakul.
Vintage has " Oath ," which uses Oath of Druids (banned in Legacy) to cheat out Eldrazi.
You can take inspiration from a variety of other decks that access huge amounts of mana, such as " High Tide ," " Amulet of Vigor ," " Enchantress " (via Serra's Sanctum , mainly), and " MUD " (via Metalworker and Cloudpost ).
Many of these don't actually need a card like Emrakul to win but sometimes play it anyway because it goes "over the top" of many other strategies.
Other approaches I've seen used (ranked in approximate order of jankiness):
Windbrisk Heights and a lot of weenies.
Summoning Trap (works well as Plan B in the Windbrisk Heights deck). Polymorph and a bunch of token-generating cards like Lingering Souls (which make creatures on the battlefield but aren't creature cards themselves).
Instant-speed reanimation with Goryo's Vengeance or Shallow Grave .
The classic reanimator spells like Exhume or Unburial Rites don't work because the big three shuffle themselves back into your library, but you can still use Goryo's Vengeance in response to the trigger.
Fist of Suns in a five-color deck, to make them all cost WUBRG.
Elvish Piper or Quicksilver Amulet .
If you're looking for a top-tier tournament deck, I recommend: Sneak and Show for Legacy: it was totally the top deck for a while.
Main down side is that it was totally the top deck for a while, of course, so many players know how to play against it.
G/R Tron for Modern.
Faster and more consistent than the other Tron decks, and pretty cheap to put together, especially if you already own the Eldrazi.
The main down side is that it is pretty weak against some of the other combo decks (like Storm) and hyper-aggressive decks.
If you're looking for a deck to play at "casual" tables, my recommendation is a Windbrisk Heights + Summoning Trap deck.
It's still very powerful but not as obviously "unfair" as the tournament combo decks — some players vehemently dislike seeing
turn-3 Karn every other game — and the aggressive/midrange creatures give you a decent fallback plan even if the whole table is dedicated to hating out your combo.
boardgames.stackexchange.com/users/1910/Alex P
Here's a non-comprehensive list of additional ideas: Braids, Conjurer Adept Call of the Wild Defense of the Heart Dream Halls (with Painter's Servant )
* Djinn of Wishes * Elvish Piper Eureka Hypergenesis Impromptu Raid Jhoira of the Ghitu * Killer Instinct Lurking Predators Myojin of Life's Web Oath of Druids Pattern of Rebirth Primal Surge Proteus Staff Show and Tell Sneak Attack
Tooth and Nail Triassic Egg
* — The creature card is cast, so you get a free turn from Emrakul, the Aeons Torn .
boardgames.stackexchange.com/users/2953/Hyppy
1) Quicksilver Amulet .
2)
Get Skittering Invasion on the board to spawn off 5 tokens and then play.
Cryptic Gateway to tap 2 of the tokens to play any Eldrazi from your hand.
3)
The harder way:
Urza lands like Urza Incubator , as well as the Urza land combo.
4) 12 post the crap out of it!
All of these ways are how my deck works, and I have been able to Emrakul, the Aeons Torn on turn 4 multiple times; as well as being able to play Eldrazi left and right by turn 6 and quickly take control of the game.
boardgames.stackexchange.com/users/8674/user8674
I have a deck that uses Deathrender , which says: Whenever equipped creature dies, you may put a creature card from your hand onto the battlefield and attach Deathrender to it.
Hows a 17/17 with annihilator 6 sound?
xD
boardgames.stackexchange.com/users/12607/10 Replies
I might suggest trying Possibility Storm .
Use it to find Emrakul and play him for free on turn 5.
Or use Quicksilver Amulet to play him on turn 4-5.
boardgames.stackexchange.com/users/9814/Karl
Decks like Eldrazi Spawn rely on swarming the field with Eldrazi Spawn tokens that you can sacrifice for colorless mana.
If you manage to get Growth Spasm in play, it becomes really easy to spam the field with tokens and play the big three.
boardgames.stackexchange.com/users/394/fabikw
You can make an Eldrazi + Cloudpost because Cloudpost will only double every time you lay one down.
With all 8 locus lands on the field equals to 36 colorless land total.
boardgames.stackexchange.com/users/15115/justin
I would recommend Belbe's Portal .
5 mana to play it, pick a creature type, then 3 and tap to put a creature of that type from your hand onto the battlefield.
boardgames.stackexchange.com/users/19778/Chance
I'm constructing an Eldrazi based deck and I'm thinking about possible ways of getting one onto the table. What I already considered:   Summoning Trap  Polymorph   Do you know any other cards like these?  Edit: I'm talking about the "big three" Legendary Eldrazi --  Emrakul, the Aeons Torn ,  Ulamog, the Infinite Gyre , and  Kozilek, Butcher of Truth .
What cards can be used to cheat Eldrazi creatures onto the table?
boardgames.stackexchange.com
<magic-the-gathering><deck-building>
boardgames.stackexchange.com/questions/7798
boardgames.stackexchange.com/users/1735/Adam Arold
The decks that do this are Legacy, Sneak and Show. You can also add Deathrender.  If you want  any  Eldrazi, like a  Pathrazer of Ulamog , you can use reanimation spells. Proven competitive decks  that do this are:   Legacy " Sneak and Show ," using  Show and Tell  and  Sneak Attack .  Modern " Tron " decks, using the power of the  UrzaTron  (Urza's Mine, Urza's Tower, and Urza's Power-Plant, which produce 7 mana from three lands) to hardcast Eldrazi. Proven competitive decks  that do this are:   Legacy " Sneak and Show ," using  Show and Tell  and  Sneak Attack .  Modern " Tron " decks, using the power of the  UrzaTron  (Urza's Mine, Urza's Tower, and Urza's Power-Plant, which produce 7 mana from three lands) to hardcast Eldrazi. The classic reanimator spells like  Exhume  or  Unburial Rites  don't work because the big three shuffle themselves back into your library, but you can still use Goryo's Vengeance  in response  to the trigger.  Deathrender card states:   Whenever equipped creature dies, you may put a creature card from your hand onto the battlefield and attach Deathrender to it.    
 If you want  any  Eldrazi, like a  Pathrazer of Ulamog , you can use reanimation spells. Proven competitive decks  that do this are:   Legacy " Sneak and Show ," using  Show and Tell  and  Sneak Attack .  Modern " Tron " decks, using the power of the  UrzaTron  (Urza's Mine, Urza's Tower, and Urza's Power-Plant, which produce 7 mana from three lands) to hardcast Eldrazi. The classic reanimator spells like  Exhume  or  Unburial Rites  don't work because the big three shuffle themselves back into your library, but you can still use Goryo's Vengeance  in response  to the trigger.   Deathrender card states:   Whenever equipped creature dies, you may put a creature card from your hand onto the battlefield and attach Deathrender to it.    You can  also take inspiration from a variety of other decks that access huge amounts of mana, such as " High Tide ," " Amulet of Vigor ," " Enchantress " (via  Serra's Sanctum , mainly), and " MUD " (via  Metalworker  and  Cloudpost ).