Foundry Assembler : Artifact Creature (Assembly Worker), casting cost of five generic mana, 3/3
It's one of the only cards in the format (or ever) to be able to brag about this
Also, the deck is very dependent on expensive quality ramp like Eye of Ugin, Ancient Tomb, or Mana Vault
Not only is she the biggest creature token of all time, shes also the biggest creature of all time full stop, discounting Un-set nonsense like B.F.M
[Activate: Main] [Once Per Turn] (You may rest the specified number of DON! cards in your cost area.): If you have 6 or less cards in your hand, look at 2 cards from the top of your deck
Having to use your mana on the turn where you want to play what you tutored for, gives more information to your opponents