Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Death Wind

Target creature gets -X/-X until end of turn.

Swamp

Barter in Blood

Each player sacrifices two creatures of their choice.

Bloodflow Connoisseur

Sacrifice a creature: Put a +1/+1 counter on Bloodflow Connoisseur.

Exile into Darkness

Target player sacrifices a creature with mana value 3 or less.
At the beginning of your upkeep, if you have more cards in hand than each opponent, you may return Exile into Darkness from your graveyard to your hand.

Blowfly Infestation

Whenever a creature dies, if it had a -1/-1 counter on it, put a -1/-1 counter on target creature.

Essence Harvest

Target player loses X life and you gain X life, where X is the greatest power among creatures you control.

Aphotic Wisps

Target creature becomes black and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)
Draw a card.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Doom Blade

Ashenmoor Cohort

Ashenmoor Cohort gets +1/+1 as long as you control another black creature.

Mind Rot

Appetite for Brains

Target opponent reveals their hand. You choose a card from it with mana value 4 or greater and exile that card.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Unholy Strength

Enchant creature
Enchanted creature gets +2/+1.

Beseech the Queen

({2/B} can be paid with any two mana or with {B}. This card's mana value is 6.)
Search your library for a card with mana value less than or equal to the number of lands you control, reveal it, put it into your hand, then shuffle.