Quest for the Gravelord

Whenever a creature dies, you may put a quest counter on Quest for the Gravelord.
Remove three quest counters from Quest for the Gravelord and sacrifice it: Create a 5/5 black Zombie Giant creature token.

Demon of Catastrophes

As an additional cost to cast this spell, sacrifice a creature.
Flying, trample

Kormus Bell

All Swamps are 1/1 black creatures that are still lands.

Phyrexian Tower

{T}: Add {C}.
{T}, Sacrifice a creature: Add {B}{B}.

Bile Urchin

Sacrifice Bile Urchin: Target player loses 1 life.

Consume Spirit

Spend only black mana on X.
Consume Spirit deals X damage to any target and you gain X life.

Swamp

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Grave Titan

Deathtouch
Whenever Grave Titan enters or attacks, create two 2/2 black Zombie creature tokens.

Drain Life

Spend only black mana on X.
Drain Life deals X damage to any target. You gain life equal to the damage dealt, but not more life than the player's life total before the damage was dealt, the planeswalker's loyalty before the damage was dealt, or the creature's toughness.

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Culling the Weak

As an additional cost to cast this spell, sacrifice a creature.
Add {B}{B}{B}{B}.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.