Choosing when to quest and what characters to quest with is really important as once theyre exerted they are open to being challenged
Crowded Crypt If youre planning on playing the long, grindy game (which token-heavy black decks often don't have much trouble doing), Crowded Crypt will passively get fairly fat, and provide you with a large army in the late game
Whether you want to reuse a burn spell, shift a removal spell onto a more deserving enemy target, or double up on a loyalty activation from a planeswalker like Chandra, Torch of Defiance, it gives you options at the exact right moment
Those enchantments tend to be very strong
In theory, you could play 19 other cards in a single turn, and then play Grapeshot to deal 20 damage to your opponent