Finale of Devastation
Oracle Text
Search your library and/or graveyard for a creature card with converted mana cost X or less and put it onto the battlefield. If you search your library this way, shuffle. If X is 10 or more, creatures you control get +X/+X and gain haste until end of turn.
But yeah, if you have 12 mana, this basically is like how I play Cathars' Crusade and Increasing Devotion, but with haste!
Can confirm by trying to make AdamSandler.deck* work. (Ramp out and kick Josu Vess, Lich Knight)
(Because he comes with eight crazy knights.)
I'm still not sure whether you'll be able to search two creatures (one from the graveyard and one from your library) but I think it's a possibility for rule interpretation.