Blood Seeker

Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Revel in Riches

Whenever a creature an opponent controls dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
At the beginning of your upkeep, if you control ten or more Treasures, you win the game.

Massacre Wurm

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

Moldervine Reclamation

Whenever a creature you control dies, you gain 1 life and draw a card.

Illness in the Ranks

Plague Engineer

Deathtouch
As Plague Engineer enters, choose a creature type.
Creatures of the chosen type your opponents control get -1/-1.

Blood Artist

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

Species Specialist

As Species Specialist enters, choose a creature type.
Whenever a creature of the chosen type dies, you may draw a card.

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.")

Kaervek, the Spiteful

Virulent Plague

Night of Souls' Betrayal

Zulaport Cutthroat

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

Engineered Plague

As Engineered Plague enters, choose a creature type.
All creatures of the chosen type get -1/-1.

Grismold, the Dreadsower

Trample
At the beginning of your end step, each player creates a 1/1 green Plant creature token.
Whenever a creature token dies, put a +1/+1 counter on Grismold, the Dreadsower.