Golgari Signet

Devouring Swarm

Flying
Sacrifice a creature: Devouring Swarm gets +1/+1 until end of turn.

Nantuko Elder

Heartstabber Mosquito

Kicker {2}{B} (You may pay an additional {2}{B} as you cast this spell.)
Flying
When Heartstabber Mosquito enters, if it was kicked, destroy target creature.

Quarry Beetle

When Quarry Beetle enters, you may return target land card from your graveyard to the battlefield.

Dross Hopper

Sacrifice a creature: Dross Hopper gains flying until end of turn.

Nantuko Vigilante

Morph {1}{G} (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 Nantuko Vigilante is turned face up, destroy target artifact or enchantment.

Font of Fertility

{1}{G}, Sacrifice Font of Fertility: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Despair

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Until end of turn, creatures you control gain menace and "Whenever this creature deals combat damage to a player, that player discards a card."

Driven

Until end of turn, creatures you control gain trample and "Whenever this creature deals combat damage to a player, draw a card."

Driven // Despair

Nantuko Husk

Sacrifice a creature: Nantuko Husk gets +2/+2 until end of turn.

Caustic Caterpillar

{1}{G}, Sacrifice Caustic Caterpillar: Destroy target artifact or enchantment.

Golgari Keyrune

{T}: Add {B} or {G}.
{B}{G}: Golgari Keyrune becomes a 2/2 black and green Insect artifact creature with deathtouch until end of turn.

Talisman of Resilience

{T}: Add {C}.
{T}: Add {B} or {G}. Talisman of Resilience deals 1 damage to you.

Mazirek, Kraul Death Priest

Flying
Whenever a player sacrifices another permanent, put a +1/+1 counter on each creature you control.

Killing Wave

For each creature, its controller sacrifices it unless they pay X life.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Vona's Hunger

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Each opponent sacrifices a creature of their choice. If you have the city's blessing, instead each opponent sacrifices half the creatures they control of their choice, rounded up.

Vampiric Rites

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.

Bane of the Living

Morph {X}{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 Bane of the Living is turned face up, all creatures get -X/-X until end of turn.

Reprocess

Sacrifice any number of artifacts, creatures, and/or lands. Draw a card for each permanent sacrificed this way.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Village Rites

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

Attrition

{B}, Sacrifice a creature: Destroy target nonblack creature.

Izoni, Thousand-Eyed

Undergrowth — When Izoni, Thousand-Eyed enters, create a 1/1 black and green Insect creature token for each creature card in your graveyard.
{B}{G}, Sacrifice another creature: You gain 1 life and draw a card.