Morbid Opportunist

Whenever one or more other creatures die, draw a card. This ability triggers only once each turn.

Withering Boon

As an additional cost to cast this spell, pay 3 life.
Counter target creature spell.

Tetzimoc, Primal Death

Deathtouch
{B}, Reveal Tetzimoc, Primal Death from your hand: Put a prey counter on target creature. Activate only during your turn.
When Tetzimoc enters, destroy each creature your opponents control with a prey counter on it.

Body Count

Spectacle {B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Draw a card for each creature that died under your control this turn.

Dark Ritual

Netherborn Altar

{T}, Put a soul counter on Netherborn Altar: Put your commander into your hand from the command zone. Then you lose 3 life for each soul counter on Netherborn Altar.

Harvester of Souls

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever another nontoken creature dies, you may draw a card.

Horobi, Death's Wail

Flying
Whenever a creature becomes the target of a spell or ability, destroy that creature.

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

Veilstone Amulet

Whenever you cast a spell, creatures you control can't be the targets of spells or abilities your opponents control this turn.

Oversold Cemetery

At the beginning of your upkeep, if you have four or more creature cards in your graveyard, you may return target creature card from your graveyard to your hand.

Unspeakable Symbol

Pay 3 life: Put a +1/+1 counter on target creature.

Xenic Poltergeist

{T}: Until your next upkeep, target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.

Touch of Darkness

One or more target creatures become black until end of turn.

Glaring Spotlight

Creatures your opponents control with hexproof can be the targets of spells and abilities you control as though they didn't have hexproof.
{3}, Sacrifice Glaring Spotlight: Creatures you control gain hexproof until end of turn and can't be blocked this turn.

Gisa, Glorious Resurrector

If a creature an opponent controls would die, exile it instead.
At the beginning of your upkeep, put all creature cards exiled with Gisa, Glorious Resurrector onto the battlefield under your control. They gain decayed. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.