Champion of Stray Souls

{3}{B}{B}, {T}, Sacrifice X other creatures: Return X target creature cards from your graveyard to the battlefield.
{5}{B}{B}: Put Champion of Stray Souls on top of your library from your graveyard.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Festering Mummy

When Festering Mummy dies, you may put a -1/-1 counter on target creature.

Sifter of Skulls

Devoid (This card has no color.)
Whenever another nontoken creature you control dies, create a 1/1 colorless Eldrazi Scion creature token. It has "Sacrifice this creature: Add {C}." ({C} represents colorless mana.)

Doomed Dissenter

When Doomed Dissenter dies, create a 2/2 black Zombie creature token.

Snow-Covered Swamp

Lord of the Accursed

Other Zombies you control get +1/+1.
{1}{B}, {T}: All Zombies gain menace until end of turn.

Death Baron

Skeletons you control and other Zombies you control get +1/+1 and have deathtouch. (Any amount of damage they deal to a creature is enough to destroy it.)

Gravedigger

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

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Open the Graves

Whenever a nontoken creature you control dies, create a 2/2 black Zombie creature token.

Disentomb

Return target creature card from your graveyard to your hand.

Eaten Alive

As an additional cost to cast this spell, sacrifice a creature or pay {3}{B}.
Exile target creature or planeswalker.