Gatekeeper of Malakir

Kicker {B} (You may pay an additional {B} as you cast this spell.)
When this creature enters, if it was kicked, target player sacrifices a creature of their choice.

Yahenni, Undying Partisan

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

Massacre Wurm

When this creature enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

Demon of Loathing

Flying, trample
Whenever this creature deals combat damage to a player, that player sacrifices a creature of their choice.

Mage Hunter

Whenever an opponent casts or copies an instant or sorcery spell, they lose 1 life.

Collective Brutality

Escalate—Discard a card. (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Target opponent reveals their hand. You choose an instant or sorcery card from it. That player discards that card.
• Target creature gets -2/-2 until end of turn.
• Target opponent loses 2 life and you gain 2 life.

Infectious Horror

Whenever this creature attacks, each opponent loses 2 life.

Blistergrub

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
When this creature dies, each opponent loses 2 life.

Swamp

Dusk Mangler

As an additional cost to cast this spell, sacrifice a creature, discard a card, or pay 4 life.
When this creature enters, each opponent sacrifices a creature of their choice, discards a card, and loses 4 life.

Fell Specter

Flying
When this creature enters, target opponent discards a card.
Whenever an opponent discards a card, that player loses 2 life.

Dogged Pursuit

At the beginning of your end step, each opponent loses 1 life and you gain 1 life.

Netherborn Phalanx

When this creature enters, each opponent loses 1 life for each creature they control.
Transmute {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Battlefield Butcher

{5}, {T}: Each opponent loses 2 life. This ability costs {1} less to activate for each creature card in your graveyard.

Drivnod, Carnage Dominus

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
{B/P}{B/P}, Exile three creature cards from your graveyard: Put an indestructible counter on Drivnod. ({B/P} can be paid with either {B} or 2 life.)

Human

Blood Artist

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

Sangromancer

Flying
Whenever a creature an opponent controls dies, you may gain 3 life.
Whenever an opponent discards a card, you may gain 3 life.

Geth's Verdict

Target player sacrifices a creature of their choice and loses 1 life.

Chainer's Edict

Target player sacrifices a creature of their choice.
Flashback {5}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Arrogant Outlaw

When this creature enters, if an opponent lost life this turn, each opponent loses 2 life and you gain 2 life.

Gloom Sower

Whenever this creature becomes blocked by a creature, that creature's controller loses 2 life and you gain 2 life.

Slaughter Specialist

When this creature enters, each opponent creates a 1/1 white Human creature token.
Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature.