Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.

Lotleth Giant

Undergrowth — When Lotleth Giant enters, it deals 1 damage to target opponent for each creature card in your graveyard.

Kagha, Shadow Archdruid

Whenever Kagha, Shadow Archdruid attacks, it gains deathtouch until end of turn. Mill two cards. (Put the top two cards of your library into your graveyard.)
Once during each of your turns, you may play a land or cast a permanent spell from among cards in your graveyard that were put there from your library this turn.

Exhume

Each player puts a creature card from their graveyard onto the battlefield.

Spore Frog

Sacrifice Spore Frog: Prevent all combat damage that would be dealt this turn.

Dread Return

Return target creature card from your graveyard to the battlefield.
Flashback—Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Crypt Rats

{X}: Crypt Rats deals X damage to each creature and each player. Spend only black mana on X.