Swamp

Raging Poltergeist

Havengul Vampire

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

Mountain

Unhallowed Pact

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

Scroll of Griselbrand

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

Reassembling Skeleton

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

Grave Exchange

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

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.

Goblin Arsonist

When Goblin Arsonist 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.

Blood Artist

Whenever Blood Artist 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.

Bloodflow Connoisseur

Sacrifice a creature: Put a +1/+1 counter on Bloodflow Connoisseur.

Soulcage Fiend

When Soulcage Fiend dies, each player loses 3 life.

Evernight Shade

{B}: Evernight Shade 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.)

Demonlord of Ashmouth

Flying
When Demonlord of Ashmouth 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.)

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 Demonic Taskmaster.

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.)

Gang of Devils

When Gang of Devils dies, it deals 3 damage divided as you choose among one, two, or three targets.

Bone Splinters

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

Driver of the Dead

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