Oubliette

When Oubliette enters, target creature phases out until Oubliette leaves the battlefield. Tap that creature as it phases in this way. (Auras and Equipment phase out with it. While permanents are phased out, they're treated as though they don't exist.)

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.)

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.

Nausea

All creatures get -1/-1 until end of turn.

Choking Sands

Destroy target non-Swamp land. If that land was nonbasic, Choking Sands deals 2 damage to the land's controller.

Grasp of Darkness

Target creature gets -4/-4 until end of turn.

Swamp

Disfigure

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

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

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.)

Barren Moor

Barren Moor enters tapped.
{T}: Add {B}.
Cycling {B} ({B}, Discard this card: Draw a card.)

Phyrexian Rager

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

Gurmag Angler

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)

Dead Weight

Enchant creature
Enchanted creature gets -2/-2.

Duress

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

Chittering Rats

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

Thorn of the Black Rose

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

Bojuka Bog

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

Cast Down

Echoing Decay

Target creature and all other creatures with the same name as that creature get -2/-2 until end of turn.

Wrench Mind

Target player discards two cards unless they discard an artifact card.

Sign in Blood

Target player draws two cards and loses 2 life.

Mortuary Mire

Mortuary Mire enters tapped.
When Mortuary Mire enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

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.

Cuombajj Witches

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