Festering Goblin

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

Fog of Gnats

Lord of the Undead

Other Zombie creatures get +1/+1.
{1}{B}, {T}: Return target Zombie card from your graveyard to your hand.

Zombie Trailblazer

Tap an untapped Zombie you control: Target land becomes a Swamp until end of turn.
Tap an untapped Zombie you control: Target creature gains swampwalk until end of turn. (It can't be blocked as long as defending player controls a Swamp.)

Tsabo's Decree

Choose a creature type. Target player reveals their hand and discards all creature cards of that type. Then destroy all creatures of that type that player controls. They can't be regenerated.

Drain Life

Spend only black mana on X.
Drain Life deals X damage to any target. You gain life equal to the damage dealt, but not more life than the player's life total before the damage was dealt, the planeswalker's loyalty before the damage was dealt, or the creature's toughness.

Soulless One

Soulless One's power and toughness are each equal to the number of Zombies on the battlefield plus the number of Zombie cards in all graveyards.

Grave Defiler

When Grave Defiler enters, reveal the top four cards of your library. Put all Zombie cards revealed this way into your hand and the rest on the bottom of your library in any order.
{1}{B}: Regenerate Grave Defiler.

Eradicate

Exile target nonblack creature. Search its controller's graveyard, hand, and library for all cards with the same name as that creature and exile them. Then that player shuffles.

Swamp

Crypt Creeper

Sacrifice Crypt Creeper: Exile target card from a graveyard.

Diabolic Edict

Target player sacrifices a creature of their choice.

Gravedigger

When Gravedigger enters, you may return target creature card from your graveyard to your hand.

Plaguebearer

{X}{X}{B}: Destroy target nonblack creature with mana value X.

Terror

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

Skinthinner

Morph {3}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Skinthinner is turned face up, destroy target nonblack creature. It can't be regenerated.

Infest

All creatures get -2/-2 until end of turn.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Scrubland

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Maggot Carrier

When Maggot Carrier enters, each player loses 1 life.

Shepherd of Rot

{T}: Each player loses 1 life for each Zombie on the battlefield.

Undead Warchief

Zombie spells you cast cost {1} less to cast.
Zombie creatures you control get +2/+1.