Have

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.)

Swamp

Feign Death

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Distress

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

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Chittering Rats

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

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.

Bojuka Bog

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

Vault Skirge

({B/P} can be paid with either {B} or 2 life.)
Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Wrench Mind

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

Liliana's Specter

Flying
When Liliana's Specter enters, each opponent discards a card.

Geth's Verdict

Target player sacrifices a creature of their choice and loses 1 life.

Ashes to Ashes

Exile two target nonartifact creatures. Ashes to Ashes deals 5 damage to you.

Unmake

Victim of Night

Destroy target non-Vampire, non-Werewolf, non-Zombie creature.

Shrivel

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.

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.)

Duress

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

Order of the Ebon Hand

Protection from white
{B}: Order of the Ebon Hand gains first strike until end of turn.
{B}{B}: Order of the Ebon Hand gets +1/+0 until end of turn.

Omen of the Dead

Flash
When Omen of the Dead enters, return target creature card from your graveyard to your hand.
{2}{B}, Sacrifice Omen of the Dead: Scry 2.

Defile

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

Grasp of Darkness

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

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.)

Dauthi Slayer

Shadow (This creature can block or be blocked by only creatures with shadow.)
Dauthi Slayer attacks each combat if able.