Its You Said OW ability lets you spend two ink to remove one damage from another character, letting you turn your unused ink into health
[card]Decree of Pain[/card] [B+]/[C] [card]Decree of Pain[/card] just left my cube to make room for the [card]Pox[/card] package, and up until then did some work
Necrogenesis If only there had been a single printing of this
Of course Spawnsire of Ulamog has a more real upper limitation in Constructed formats where youre limited by the number of cards in your sideboard, but either way pressing the big shiny button with a 20 on it should win you the game on the spot
Wheel and Jar on the other hand are just a bit too much, you need to put in too much effort in building around them to make them viable inclusions
And in case you're worried about getting taken advantage of, you can set up trading controls that only allow like-for-like trades, so you don't accidentally trade a rare card for a common one