Pitiless Plunderer

Whenever another creature you control dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Obzedat, Ghost Council

When Obzedat, Ghost Council enters the battlefield, target opponent loses 2 life and you gain 2 life.
At the beginning of your end step, you may exile Obzedat. If you do, return it to the battlefield under its owner's control at the beginning of your next upkeep. It gains haste.

Pawn of Ulamog

Whenever Pawn of Ulamog or another nontoken creature you control dies, you may create a 0/1 colorless Eldrazi Spawn creature token. It has "Sacrifice this creature: Add {C}."

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Graveblade Marauder

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever Graveblade Marauder deals combat damage to a player, that player loses life equal to the number of creature cards in your graveyard.

Tithe Drinker

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)

Basilica Bell-Haunt

When Basilica Bell-Haunt enters the battlefield, each opponent discards a card and you gain 3 life.

Pontiff of Blight

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Other creatures you control have extort. (If a creature has multiple instances of extort, each triggers separately.)

Syndicate Enforcer

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)

Ayli, Eternal Pilgrim

Deathtouch
{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.

Vampire Nighthawk

Teysa, Envoy of Ghosts

Vigilance, protection from creatures
Whenever a creature deals combat damage to you, destroy that creature. Create a 1/1 white and black Spirit creature token with flying.

Fleshbag Marauder

When Fleshbag Marauder enters the battlefield, each player sacrifices a creature.

Merciless Executioner

When Merciless Executioner enters the battlefield, each player sacrifices a creature.

Disciple of Griselbrand

{1}, Sacrifice a creature: You gain life equal to the sacrificed creature's toughness.

Orzhov Enforcer

Deathtouch
Afterlife 1 (When this creature dies, create a 1/1 white and black Spirit creature token with flying.)

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, Serra Ascendant gets +5/+5 and has flying.

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.

Blood Artist

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

Bishop of Rebirth

Vigilance
Whenever Bishop of Rebirth attacks, you may return target creature card with mana value 3 or less from your graveyard to the battlefield.

Suture Priest

Whenever another creature enters the battlefield under your control, you may gain 1 life.
Whenever a creature enters the battlefield under an opponent's control, you may have that player lose 1 life.

Tattered Mummy

When Tattered Mummy dies, each opponent loses 2 life.

Zulaport Cutthroat

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

Doomed Traveler

When Doomed Traveler dies, create a 1/1 white Spirit creature token with flying.