While it only takes second place because its not quite as strong as the #1 spot, its got a lot going for it
Avatar Aang // Aang, Master of Elements is a double-faced card, a design reserved for characters who undergo a big transformation
Four years later those cards finally appeared in a Secret Lair product
The limitation here is relevant, but as long as you have something die that isnt named Dracolith, it will basically be in your hand again, ready to be cast, and thats pretty insane
With two connected abilities, Xavier Sal can tap to either remove a counter from a permanent you control to populate, or to sacrifice another creature to proliferate
This is due to the fact that auras can be placed at the intersection of four squares