Devour in Shadow

Destroy target creature. It can't be regenerated. You lose life equal to that creature's toughness.

Shadow Alley Denizen

Whenever another black creature you control enters, target creature gains intimidate until end of turn. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Kiku's Shadow

Target creature deals damage to itself equal to its power.

Shadowcloak Vampire

Pay 2 life: Shadowcloak Vampire gains flying until end of turn. (It can't be blocked except by creatures with flying or reach.)

Death's Shadow

Death's Shadow gets -X/-X, where X is your life total.

Dance of Shadows

Creatures you control get +1/+0 and gain fear until end of turn. (They can't be blocked except by artifact creatures and/or black creatures.)

Armor of Shadows

Until end of turn, target creature gets +1/+0 and gains indestructible. (Damage and effects that say "destroy" don't destroy it.)

Spiteful Shadows

Enchant creature
Whenever enchanted creature is dealt damage, it deals that much damage to its controller.

Reach of Shadows

Destroy target creature that's one or more colors.

Embrose, Dean of Shadow

{T}: Put a +1/+1 counter on another target creature, then Embrose, Dean of Shadow deals 2 damage to that creature.
Whenever a creature you control with a +1/+1 counter on it dies, draw a card.

Shaile, Dean of Radiance

Flying, vigilance
{T}: Put a +1/+1 counter on each creature that entered the battlefield under your control this turn.

Shaile, Dean of Radiance // Embrose, Dean of Shadow

Tergrid's Shadow

Each player sacrifices two creatures.
Foretell {2}{B}{B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Perilous Shadow

{1}{B}: Perilous Shadow gets +2/+2 until end of turn.

Davriel's Shadowfugue

Target player discards two cards and loses 2 life.

Shadow of Mortality

If your life total is less than your starting life total, this spell costs {X} less to cast, where X is the difference.