Doomgape

Trample
At the beginning of your upkeep, sacrifice a creature. You gain life equal to that creature's toughness.

Abyssal Nightstalker

Whenever Abyssal Nightstalker attacks and isn't blocked, defending player discards a card.

Terror

Destroy target nonartifact, nonblack creature. It can't be regenerated.

Swamp

Grandmother Sengir

{1}{B}, {T}: Target creature gets -1/-1 until end of turn.

Waste Not

Whenever an opponent discards a creature card, create a 2/2 black Zombie creature token.
Whenever an opponent discards a land card, add {B}{B}.
Whenever an opponent discards a noncreature, nonland card, draw a card.

Tevesh Szat, Doom of Fools

+2: Create two 0/1 black Thrull creature tokens.
+1: You may sacrifice another creature or planeswalker. If you do, draw two cards, then draw another card if the sacrificed permanent was a commander.
−10: Gain control of all commanders. Put all commanders from the command zone onto the battlefield under your control.
Tevesh Szat, Doom of Fools can be your commander.
Partner

Grim Backwoods

{T}: Add {C}.
{2}{B}{G}, {T}, Sacrifice a creature: Draw a card.

Nemesis of Reason

Whenever Nemesis of Reason attacks, defending player mills ten cards.