Koma is so good that it will probably push players to run sacrifice-based removal like Extract a Confession or Deadly Brew
But for competitive play, prioritize Sets 9+
Counting Commander, Masters, Jumpstart, Universes Beyond, remasters, and Ultimate Masters, plus upcoming sets and previous releases with exciting cards, the total tops 200
and along with other two-for-one cards like Force of Vigor, they are some of the most powerful cards in the game: they offer instant-speed interaction for no mana
Nim Deathmantle has the added feature that it would bring a recently deceased creature back from the graveyard as a Zombie, allowing my creature type anthems to kick in and let me start drawing cards