Have

The Monarch

At the beginning of your end step, draw a card.
Whenever a creature deals combat damage to you, its controller becomes the monarch.

Chittering Rats

When Chittering Rats enters, target opponent puts a card from their hand on top of their library.

Swamp

Cuombajj Witches

{T}: Cuombajj Witches deals 1 damage to any target and 1 damage to any target of an opponent's choice.

Chainer's Edict

Target player sacrifices a creature of their choice.
Flashback {5}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Sign in Blood

Target player draws two cards and loses 2 life.

Consuming Sepulcher

At the beginning of your upkeep, each opponent loses 1 life and you gain 1 life.

Tithing Blade

When Tithing Blade enters, each opponent sacrifices a creature of their choice.
Craft with creature {4}{B} ({4}{B}, Exile this artifact, Exile a creature you control or a creature card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Tithing Blade // Consuming Sepulcher

Snuff Out

If you control a Swamp, you may pay 4 life rather than pay this spell's mana cost.
Destroy target nonblack creature. It can't be regenerated.

Distress

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

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Exhume

Each player puts a creature card from their graveyard onto the battlefield.

Trespasser's Curse

Enchant player
Whenever a creature enchanted player controls enters, that player loses 1 life and you gain 1 life.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel 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.)

Pestilence

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pestilence.
{B}: Pestilence deals 1 damage to each creature and each player.

Suffocating Fumes

Creatures your opponents control get -1/-1 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Phyrexian Rager

When Phyrexian Rager enters, you draw a card and you lose 1 life.

Unexpected Fangs

Put a +1/+1 counter and a lifelink counter on target creature.

Duress

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

Bojuka Bog

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

Witch's Cottage

({T}: Add {B}.)
Witch's Cottage enters tapped unless you control three or more other Swamps.
When Witch's Cottage enters untapped, you may put target creature card from your graveyard on top of your library.

Thorn of the Black Rose

Deathtouch
When Thorn of the Black Rose enters, you become the monarch.

Troll of Khazad-dûm

Troll of Khazad-dûm can't be blocked except by three or more creatures.
Swampcycling {1} ({1}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Nihil Spellbomb

{T}, Sacrifice Nihil Spellbomb: Exile target player's graveyard.
When Nihil Spellbomb is put into a graveyard from the battlefield, you may pay {B}. If you do, draw a card.