Havengul Vampire

Whenever this creature deals combat damage to a player, put a +1/+1 counter on it.
Whenever another creature dies, put a +1/+1 counter on this creature.

Mountain

Harvester of Souls

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever another nontoken creature dies, you may draw a card.

Evernight Shade

{B}: This creature gets +1/+1 until end of turn.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Driver of the Dead

When this creature dies, return target creature card with mana value 2 or less from your graveyard to the battlefield.

Barter in Blood

Each player sacrifices two creatures of their choice.

Demonic Taskmaster

Flying
At the beginning of your upkeep, sacrifice a creature other than this creature.

Swamp

Butcher Ghoul

Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Hunted Ghoul

Grave Exchange

Return target creature card from your graveyard to your hand. Target player sacrifices a creature of their choice.

Unhallowed Pact

Enchant creature
When enchanted creature dies, return that card to the battlefield under your control.

Gang of Devils

When this creature dies, it deals 3 damage divided as you choose among one, two, or three targets.

Demonlord of Ashmouth

Flying
When this creature enters, exile it unless you sacrifice another creature.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Scroll of Griselbrand

{1}, Sacrifice this artifact: Target opponent discards a card. If you control a Demon, that player loses 3 life.

Bloodflow Connoisseur

Sacrifice a creature: Put a +1/+1 counter on this creature.

Soulcage Fiend

When this creature dies, each player loses 3 life.

Goblin Arsonist

When this creature dies, you may have it deal 1 damage to any target.

Maalfeld Twins

When this creature dies, create two 2/2 black Zombie creature tokens.

Raging Poltergeist

Blood Artist

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

Fling

As an additional cost to cast this spell, sacrifice a creature.
Fling deals damage equal to the sacrificed creature's power to any target.

Reassembling Skeleton

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

Bone Splinters

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