Morkrut Behemoth

As an additional cost to cast this spell, sacrifice a creature or pay {1}{B}.
Menace (This creature can't be blocked except by two or more creatures.)

Orzhov Enforcer

Deathtouch
Afterlife 1 (When this creature dies, create a 1/1 white and black Spirit creature token with flying.)

Recover

Return target creature card from your graveyard to your hand.
Draw a card.

Awoken Demon

Ecstatic Awakener

{2}{B}, Sacrifice another creature: Draw a card, then transform this creature. Activate only once each turn.

Ecstatic Awakener // Awoken Demon

Demon of Catastrophes

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

Reassembling Skeleton

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

Skyclave Shade

Kicker {2}{B}
This creature can't block.
If this creature was kicked, it enters with two +1/+1 counters on it.
Landfall — Whenever a land you control enters, if this card is in your graveyard and it's your turn, you may cast it from your graveyard this turn.

Tenacious Underdog

Blitz—{2}{B}{B}, Pay 2 life. (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)
You may cast this card from your graveyard using its blitz ability.

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Swamp

Doomed Dissenter

When this creature dies, create a 2/2 black Zombie creature token.

Skyclave Shadowcat

{1}{B}, Sacrifice another creature: Put a +1/+1 counter on this creature.
Whenever a creature you control with a +1/+1 counter on it dies, draw a card.

Vicious Offering

Kicker—Sacrifice a creature. (You may sacrifice a creature in addition to any other costs as you cast this spell.)
Target creature gets -2/-2 until end of turn. If this spell was kicked, that creature gets -5/-5 until end of turn instead.

Cult Conscript

This creature enters tapped.
{1}{B}: Return this card from your graveyard to the battlefield. Activate only if a non-Skeleton creature died under your control this turn.

Deathbloom Thallid

When this creature dies, create a 1/1 green Saproling creature token.

Priest of Forgotten Gods

{T}, Sacrifice two other creatures: Any number of target players each lose 2 life and sacrifice a creature of their choice. You add {B}{B} and draw a card.

Undercity Necrolisk

{1}, Sacrifice another creature: Put a +1/+1 counter on this creature. It gains menace until end of turn. Activate only as a sorcery. (It can't be blocked except by two or more creatures.)

Priest of the Blood Rite

When this creature enters, create a 5/5 black Demon creature token with flying.
At the beginning of your upkeep, you lose 2 life.