Swamp

Writhing Necromass

This spell costs {1} less to cast for each creature card in your graveyard.
Deathtouch

Doom Blade

Go for the Throat

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters the battlefield, 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.)

Gisa, Glorious Resurrector

If a creature an opponent controls would die, exile it instead.
At the beginning of your upkeep, put all creature cards exiled with Gisa, Glorious Resurrector onto the battlefield under your control. They gain decayed. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Gisa, the Hellraiser

Ward—{2}, Pay 2 life.
Skeletons and Zombies you control get +1/+1 and have menace.
Whenever you commit a crime, create two tapped 2/2 blue and black Zombie Rogue creature tokens. This ability triggers only once each turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

Gravepurge

Put any number of target creature cards from your graveyard on top of your library.
Draw a card.

Cult Conscript

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

Piranha Marsh

Piranha Marsh enters the battlefield tapped.
When Piranha Marsh enters the battlefield, target player loses 1 life.
{T}: Add {B}.

Ayara, First of Locthwain

Whenever Ayara, First of Locthwain or another black creature enters the battlefield under your control, each opponent loses 1 life and you gain 1 life.
{T}, Sacrifice another black creature: Draw a card.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Altar's Reap

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

Bojuka Bog

Bojuka Bog enters the battlefield tapped.
When Bojuka Bog enters the battlefield, exile target player's graveyard.
{T}: Add {B}.

Dark Ritual

Appetite for Brains

Target opponent reveals their hand. You choose a card from it with mana value 4 or greater and exile that card.

Dying Wish

Enchant creature you control
When enchanted creature dies, target player loses X life and you gain X life, where X is its power.

Diregraf Ghoul

Diregraf Ghoul enters the battlefield tapped.

Crypt Creeper

Sacrifice Crypt Creeper: Exile target card from a graveyard.

Sol Ring

Cemetery Reaper

Other Zombie creatures you control get +1/+1.
{2}{B}, {T}: Exile target creature card from a graveyard. Create a 2/2 black Zombie creature token.

Gisa's Favorite Shovel

Equipped creature gets +2/+0 and has menace.
Whenever equipped creature attacks, defending player sacrifices a creature. If they do, you create a Walker token. (It's a 2/2 black Zombie creature.)
Equip {4}

Death Baron

Skeletons you control and other Zombies you control get +1/+1 and have deathtouch.

Relic of Legends

{T}: Add one mana of any color.
Tap an untapped legendary creature you control: Add one mana of any color.

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters the battlefield, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Despise

Target opponent reveals their hand. You choose a creature or planeswalker card from it. That player discards that card.