Defiant Bloodlord

Flying
Whenever you gain life, target opponent loses that much life.

Vermin Gorger

{T}, Sacrifice another creature: Each opponent loses 2 life and you gain 2 life.

Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Kambal, Consul of Allocation

Whenever an opponent casts a noncreature spell, that player loses 2 life and you gain 2 life.

Ayli, Eternal Pilgrim

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
{1}, Sacrifice another creature: You gain life equal to the sacrificed creature's toughness.
{1}{W}{B}, Sacrifice another creature: Exile target nonland permanent. Activate only if you have at least 10 life more than your starting life total.

Athreos, God of Passage

Indestructible
As long as your devotion to white and black is less than seven, Athreos isn't a creature.
Whenever another creature you own dies, return it to your hand unless target opponent pays 3 life.

Wayward Disciple

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

Pious Evangel

Whenever this creature or another creature you control enters, you gain 1 life.
{2}, {T}, Sacrifice another permanent: Transform this creature.

Pious Evangel // Wayward Disciple

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Vizkopa Guildmage

{1}{W}{B}: Target creature gains lifelink until end of turn.
{1}{W}{B}: Whenever you gain life this turn, each opponent loses that much life.

Zulaport Cutthroat

Whenever this creature or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Teysa Karlov

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Creature tokens you control have vigilance and lifelink.