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.

Wicked Akuba

{B}: Target player dealt damage by this creature this turn loses 1 life.

Duress

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

Gray Merchant of Asphodel

When this creature 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.)

Night's Whisper

Hopeless Nightmare

When this enchantment enters, each opponent discards a card and loses 2 life.
When this enchantment is put into a graveyard from the battlefield, scry 2.
{2}{B}: Sacrifice this enchantment.

Order of the Ebon Hand

Protection from white
{B}: This creature gains first strike until end of turn.
{B}{B}: This creature gets +1/+0 until end of turn.

Bone Shards

As an additional cost to cast this spell, sacrifice a creature or discard a card.
Destroy target creature or planeswalker.

Cuombajj Witches

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

Okiba-Gang Shinobi

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, that player discards two cards.

Swamp

Sign in Blood

Target player draws two cards and loses 2 life.

Chittering Rats

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

Toxin Analysis

Target creature gains deathtouch and lifelink until end of turn. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Trespasser's Curse

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

Blood Fountain

When this artifact enters, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")
{3}{B}, {T}, Sacrifice this artifact: Return up to two target creature cards from your graveyard to your hand.

Faerie Macabre

Flying
Discard this card: Exile up to two target cards from graveyards.

Crypt Rats

{X}: This creature deals X damage to each creature and each player. Spend only black mana on X.

Defile

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

Cast Down

Dauthi Slayer

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

Nausea

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

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.