I use the Mayday games sleeves for all my Dominion cards.
The sets of 10 Kingdom cards will still fit in their slots in the box just fine.
More numerous cards (like the Treasure and VPs) either will not fit at all, or will have to be jammed in pretty tightly.
Personally, I put Dominion, Intrigue, Seaside and Alchemy into two "long boxes" that you see used for CCGs, with little labeled tabs I printed from BGG separating them.
This takes up a lot less room than the 3 large boxes and half-size Alchemy box, and makes the game portable.
Prosperity is still in its original box since I'm out of space in my long boxes.
I keep all the Kingdom cards in their original slot, but keep Colony and Platinum in some of the larger unused slots rather than the ones labeled for them, because I don't like the tight fit.
boardgames.stackexchange.com/users/32/lilserf
Just to offer another point of view, I also use the Mayday sleeves for my Dominion cards.
I have no problem fitting the cards in the original box in the correct slots, except for Coppers.
My solution was to just not sleeve all the Coppers, since I have yet to play a game where I came anywhere close to using all of them.
boardgames.stackexchange.com/users/94/David Fullerton
When I sleeved some of the cards from Dominion: Dark Ages with premium Mayday sleeves, they wouldn't fit back in the box.
The card slots aren't even close to being wide enough because the card sleeves make the cards a little taller.
I found that strange, because I had no problem with Dominion, the Dominion base card set, or Dominion: Seaside.
To fix this issue I ordered an Organizer for Dominion made by ElephantCraftsShop.
It claims to hold at least 1500 sleeved cards, comes with special inserts for tokens, and fits into any full-sized dominion box.
I'll let you know how that works when it comes in the mail.
Here's a link to what it looks like. https://www.etsy.com/listing/469564688/organizer-for-dominion-board-game?ref=hp_rv ...
After receiving this in the mail, assembling it, and filling it with cards from Dominion, Dominion Update Pack, Dominion: Seaside, and Dominion: Dark Ages, I realized I still had a major project in front of me.
Yes, It can hold about 1,500 sleeved cards, but I found that I couldn't easily get them out when they're packed that tightly.
So I removed my Coppers, Silvers, and Golds, and put them in the yellow base cards box.
Then I had to make my own card dividers for the rest.
I spent hours cutting out tabbed dividers from poster-board and sticking labels on them.
It was a huge project.
It's pretty awesome now that it's done, but this product is not a complete solution as of itself.
boardgames.stackexchange.com/users/18744/Ned Strong
I also used the Mayday sleeves.
I've conslidated Dominion and Intrigue into one box by removing the inserts, and putting each type of card into a snak-sized ziplock.
I might be able to get one more box integrated in.... but will be tight.
I was unable to get all of it in the tray, however, due to the coppers and curses no longer fitting their slots.
Which is why I went to baggies.
boardgames.stackexchange.com/users/1047/aramis
I use the premium Mayday sleeves as well and own both Dominion (1st edition) and Dominion Update Pack.
I sleeved them all except the blank cards and randomizing cards with premium Mayday sleeves.
I moved all money to a separate place — I use the yellow base cards box to hold Copper, Silver, and Gold in the three compartments.
All other cards fit comfortably into the original box.
boardgames.stackexchange.com/users/18744/Ned Strong
I am considering getting card protectors for my dominion game. Do the cards still fit back into their slots in the box?  The ones I was thinking about were the ones advertised in the box with dominion from Mayday Games.
Can I use sleeve protectors for Dominion cards and still fit them back into the box?
boardgames.stackexchange.com
<dominion>
boardgames.stackexchange.com/questions/2833
boardgames.stackexchange.com/users/832/Andrey
They may not fit back into the box with sleeves on or they may be so tightly packed in that they are hard to get out again. When the cards are sleeved from Dominion: Dark Ages with premium Mayday sleeves, they don't all fit back in the box. The box can hold 1,500 sleeved cards, but it is not then easy to get them out when they're packed that tightly.
When the cards are sleeved from Dominion: Dark Ages with premium Mayday sleeves, they don't all fit back in the box. The box can hold 1,500 sleeved cards, but it is not then easy to get them out when they're packed that tightly.