Singleton Factory

[Guevara59]

This card is gonna be way to cheap most likey.  I think its a cool idea and im pretty much positive that it will be shot down instantly. 

Singleton Factory
5
Artifact
When --this-- comes into play, each player searches their libraries, hands, and graveyards, and removes from the game copies of each card in their library until there is one copy of each card.  When --this-- leaves play, return all cards removed this way into their respective places.

I think this is an extremely card to shake things up a bit... possibly broken... but fun.

[jro]

This would have to be done with a reveal to verify that it was done correctly, and would take way too damn long to resolve.  Also, you didn't create an exception for basic land.

Bazaar of Wonders and Leyline of Singularity try to do this kind of thing (only letting you play one of something), but they're a lot more sensible.

[ELD]

I'll be adding this to my Sharazard + Fork + Soldier of Fortune deck.  Now instead of just making my opponent shuffle their deck for no reason, I'll be able to use Goblin Welder to weld this artifact in and out of play repeatedly.  If they won't concede to that, they might just have a heart attack from all the needless busy work. 

[Harlequin]

I'll be adding this to my Sharazard + Fork + Soldier of Fortune deck.  Now instead of just making my opponent shuffle their deck for no reason, I'll be able to use Goblin Welder to weld this artifact in and out of play repeatedly.  If they won't concede to that, they might just have a heart attack from all the needless busy work. 

LOL

Yeah, I agree that this card is a bit too much work for not that important of an effect. 

[Matt]

I think you want this:

If a nonland card is played or would come into play, if a card with the same name is in any graveyard or in play, remove that card from the game. (Spells removed in this manner don't resolve.)

That version is cleaner, requires vastly less work, and can be abused with cards that have an effect without being played - such as the Forecast cards from Dissension.

Alternately you could do this:

Enchantment
Whenever a player plays a spell, if a card of the same name is in any graveyard, counter that spell.
When ~this~ comes into play, you may search your library for a card named Leyline of Singularity and put it into play.

Which basically does what you want it to.

[Darkenslight]

Matt: I like your first incernation design, but I think it should also affect nonbasic lands, too.

[Guevara59]

I really like Matt's variation.  It costs a lot less work and still does pretty much what i want it to do.

[Matt]

I actually like that it doesn't affect nonbasic lands. That gives you more ways to work around the drawback. I could conceivably see this in that 43 lands deck from Legacy.