Nightmare

Whenever this creature attacks or blocks, each opponent exiles the top two cards of their library.

Staff of the Death Magus

Whenever you cast a black spell or a Swamp you control enters, you gain 1 life.

Zof Shade

{2}{B}: Zof Shade gets +2/+2 until end of turn.

Sign in Blood

Target player draws two cards and loses 2 life.

Witch's Familiar

Flesh to Dust

Destroy target creature. It can't be regenerated.

Sengir Vampire

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a creature dealt damage by Sengir Vampire this turn dies, put a +1/+1 counter on Sengir Vampire.

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Walking Corpse

Festergloom

Nonblack creatures get -1/-1 until end of turn.

Swamp

Gravedigger

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

Mind Rot

Crippling Blight

Enchant creature
Enchanted creature gets -1/-1 and can't block.

Paragon of Open Graves

Other black creatures you control get +1/+1.
{2}{B}, {T}: Another target black creature you control gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)