Giant Scorpion

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

Doom Blade

Swamp

Vampire Nighthawk

Shadowborn Demon

Flying
When Shadowborn Demon enters the battlefield, destroy target non-Demon creature.
At the beginning of your upkeep, if there are fewer than six creature cards in your graveyard, sacrifice a creature.

Dismember

({B/P} can be paid with either {B} or 2 life.)
Target creature gets -5/-5 until end of turn.

Go for the Throat

Victim of Night

Destroy target non-Vampire, non-Werewolf, non-Zombie creature.

Sign in Blood

Target player draws two cards and loses 2 life.

Asphodel Wanderer

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Sewer Shambler

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
Scavenge {2}{B} ({2}{B}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters the battlefield, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Fate Unraveler

Whenever an opponent draws a card, Fate Unraveler deals 1 damage to that player.

Crypt Incursion

Exile all creature cards from target player's graveyard. You gain 3 life for each card exiled this way.