Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Hideous End

Destroy target nonblack creature. Its controller loses 2 life.

Carrier Thrall

When Carrier Thrall dies, create a 1/1 colorless Eldrazi Scion creature token. It has "Sacrifice this creature: Add {C}."

Fetid Imp

Flying
{B}: Fetid Imp gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Mire's Toll

Target player reveals a number of cards from their hand equal to the number of Swamps you control. You choose one of them. That player discards that card.

Ob Nixilis Reignited

+1: You draw a card and you lose 1 life.
−3: Destroy target creature.
−8: Target opponent gets an emblem with "Whenever a player draws a card, you lose 2 life."

Innocent Blood

Liliana, the Last Hope

+1: Up to one target creature gets -2/-1 until your next turn.
−2: Mill two cards, then you may return a creature card from your graveyard to your hand.
−7: You get an emblem with "At the beginning of your end step, create X 2/2 black Zombie creature tokens, where X is two plus the number of Zombies you control."

Smallpox

Each player loses 1 life, discards a card, sacrifices a creature, then sacrifices a land.

Unhallowed Pact

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

Swamp

Bala Ged Scorpion

When Bala Ged Scorpion enters the battlefield, you may destroy target creature with power 1 or less.

Ob Nixilis, Unshackled

Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis, Unshackled.

Blistergrub

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
When Blistergrub dies, each opponent loses 2 life.

Leechridden Swamp

({T}: Add {B}.)
Leechridden Swamp enters the battlefield tapped.
{B}, {T}: Each opponent loses 1 life. Activate only if you control two or more black permanents.

Cadaver Imp

Flying
When Cadaver Imp enters the battlefield, you may return target creature card from your graveyard to your hand.

Tendrils of Corruption

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

Giant Scorpion

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Squelching Leeches

Squelching Leeches's power and toughness are each equal to the number of Swamps you control.

Disfigure

Target creature gets -2/-2 until end of turn.

Despoiler of Souls

Despoiler of Souls can't block.
{B}{B}, Exile two other creature cards from your graveyard: Return Despoiler of Souls from your graveyard to the battlefield.

Renegade Demon

Desecration Demon

Flying
At the beginning of each combat, any opponent may sacrifice a creature. If a player does, tap Desecration Demon and put a +1/+1 counter on it.

Shadows of the Past

Whenever a creature dies, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)
{4}{B}: Each opponent loses 2 life and you gain 2 life. Activate only if there are four or more creature cards in your graveyard.

Grim Discovery

Choose one or both —
• Return target creature card from your graveyard to your hand.
• Return target land card from your graveyard to your hand.

Foul Imp

Flying
When Foul Imp enters the battlefield, you lose 2 life.

Indulgent Tormentor

Flying
At the beginning of your upkeep, draw a card unless target opponent sacrifices a creature or pays 3 life.

Ambition's Cost

You draw three cards and you lose 3 life.

Liliana Vess

+1: Target player discards a card.
−2: Search your library for a card, then shuffle and put that card on top.
−8: Put all creature cards from all graveyards onto the battlefield under your control.