Crypt Rats

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

Grave Scrabbler

Madness {1}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
When Grave Scrabbler enters, if its madness cost was paid, you may return target creature card from a graveyard to its owner's hand.

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Halana, Kessig Ranger

Reach
Whenever another creature you control enters, you may pay {2}. When you do, that creature deals damage equal to its power to target creature.
Partner (You can have two commanders if both have partner.)

Spore Frog

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

Shred Memory

Exile up to four target cards from a single graveyard.
Transmute {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Sakura-Tribe Elder

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

Tortured Existence

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

Tormod, the Desecrator

Whenever one or more cards leave your graveyard, create a tapped 2/2 black Zombie creature token.
Partner (You can have two commanders if both have partner.)