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.)

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.

Defile

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

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Sunlit Marsh

({T}: Add {W} or {B}.)
Sunlit Marsh enters tapped.

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.)

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.

Chittering Rats

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

Swamp

Thorn of the Black Rose

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

Cast Down

Vampire Sovereign

Flying
When Vampire Sovereign enters, target opponent loses 3 life and you gain 3 life.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Cuombajj Witches

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

Drown in Sorrow

All creatures get -2/-2 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

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.