Marshmist Titan

This spell costs {X} less to cast, where X is your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Mark of the Vampire

Enchant creature
Enchanted creature gets +2/+2 and has lifelink.

Prowling Pangolin

When Prowling Pangolin enters, any player may sacrifice two creatures of their choice. If a player does, sacrifice Prowling Pangolin.

Skittering Monstrosity

When you cast a creature spell, sacrifice Skittering Monstrosity.

Stab Wound

Enchant creature
Enchanted creature gets -2/-2.
At the beginning of the upkeep of enchanted creature's controller, that player loses 2 life.

Devour Flesh

Target player sacrifices a creature of their choice, then gains life equal to that creature's toughness.

Demonic Bargain

Exile the top thirteen cards of your library, then search your library for a card. Put that card into your hand, then shuffle.

Hidden Horror

When Hidden Horror enters, sacrifice it unless you discard a creature card.

Bogstomper

Everglades

Everglades enters tapped.
When Everglades enters, sacrifice it unless you return an untapped Swamp you control to its owner's hand.
{T}: Add {C}{B}.

Haunting Hymn

Target player discards two cards. If you cast this spell during your main phase, that player discards four cards instead.

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."

Sutured Ghoul

Trample
As Sutured Ghoul enters, exile any number of creature cards from your graveyard.
Sutured Ghoul's power is equal to the total power of the exiled cards and its toughness is equal to their total toughness.

Swamp

Fatal Blow

Destroy target creature that was dealt damage this turn. It can't be regenerated.