Gray Merchant of Asphodel

When this creature enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Omen of the Dead

Flash
When this enchantment enters, return target creature card from your graveyard to your hand.
{2}{B}, Sacrifice this enchantment: Scry 2.

Yarok's Fenlurker

When this creature enters, each opponent exiles a card from their hand.
{2}{B}: This creature gets +1/+1 until end of turn.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Vraska's Contempt

Exile target creature or planeswalker. You gain 2 life.

Ayara, First of Locthwain

Whenever Ayara or another black creature you control enters, each opponent loses 1 life and you gain 1 life.
{T}, Sacrifice another black creature: Draw a card.

Swift End

Destroy target creature or planeswalker. You lose 2 life. (Then exile this card. You may cast the creature later from exile.)

Murderous Rider

Lifelink
When this creature dies, put it on the bottom of its owner's library.

Murderous Rider // Swift End

Brain Maggot

When this creature enters, target opponent reveals their hand and you choose a nonland card from it. Exile that card until this creature leaves the battlefield.

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Phyrexian Obliterator

Trample
Whenever a source deals damage to this creature, that source's controller sacrifices that many permanents of their choice.

Castle Locthwain

This land enters tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

Knight of the Ebon Legion

{2}{B}: This creature gets +3/+3 and gains deathtouch until end of turn.
At the beginning of your end step, if a player lost 4 or more life this turn, put a +1/+1 counter on this creature. (Damage causes loss of life.)