Fleshbag Marauder

When this creature enters, each player sacrifices a creature of their choice.

Blood Artist

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

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Archfiend of Depravity

Flying
At the beginning of each opponent's end step, that player chooses up to two creatures they control, then sacrifices the rest.

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Gatekeeper of Malakir

Kicker {B} (You may pay an additional {B} as you cast this spell.)
When this creature enters, if it was kicked, target player sacrifices a creature of their choice.

Malevolent Awakening

{1}{B}{B}, Sacrifice a creature: Return target creature card from your graveyard to your hand.

Avatar of Woe

If there are ten or more creature cards total in all graveyards, this spell costs {6} less to cast.
Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{T}: Destroy target creature. It can't be regenerated.

Geth's Verdict

Target player sacrifices a creature of their choice and loses 1 life.

Swamp

Mortivore

Mortivore's power and toughness are each equal to the number of creature cards in all graveyards.
{B}: Regenerate this creature. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.