Bubbling Muck

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

Initiates of the Ebon Hand

{1}: Add {B}. If this ability has been activated four or more times this turn, sacrifice Initiates of the Ebon Hand at the beginning of the next end step.

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Dark Banishing

Destroy target nonblack creature. It can't be regenerated.

Barren Moor

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

Hound of the Farbogs

Delirium — Hound of the Farbogs has menace as long as there are four or more card types among cards in your graveyard. (A creature with menace can't be blocked except by two or more creatures.)

Swamp

Dead Weight

Enchant creature
Enchanted creature gets -2/-2.

Merciless Resolve

As an additional cost to cast this spell, sacrifice a creature or land.
Draw two cards.

Shamble Back

Exile target creature card from a graveyard. Create a 2/2 black Zombie creature token. You gain 2 life.

Rancid Rats

Skulk (This creature can't be blocked by creatures with greater power.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Rottenheart Ghoul

When Rottenheart Ghoul dies, target player discards a card.

Grotesque Mutation

Target creature gets +3/+1 and gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Festering Goblin

When Festering Goblin dies, target creature gets -1/-1 until end of turn.

Dark Bargain

Look at the top three cards of your library. Put two of them into your hand and the other into your graveyard. Dark Bargain deals 2 damage to you.