Mycoloth

Devour 2 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it.)
At the beginning of your upkeep, create a 1/1 green Saproling creature token for each +1/+1 counter on Mycoloth.

Marrow Chomper

Devour 2 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it.)
When Marrow Chomper enters the battlefield, you gain 2 life for each creature it devoured.

Haruspex

Rapacious Hunger — Whenever another creature dies, put a +1/+1 counter on Haruspex.
Devouring Monster — {T}, Remove X +1/+1 counters from Haruspex: Add X mana of any one color.

Fecundity

Whenever a creature dies, that creature's controller may draw a card.

Korvold, Fae-Cursed King

Flying
Whenever Korvold, Fae-Cursed King enters the battlefield or attacks, sacrifice another permanent.
Whenever you sacrifice a permanent, put a +1/+1 counter on Korvold and draw a card.

Liliana, Dreadhorde General

Whenever a creature you control dies, draw a card.
+1: Create a 2/2 black Zombie creature token.
−4: Each player sacrifices two creatures.
−9: Each opponent chooses a permanent they control of each permanent type and sacrifices the rest.

Vogar, Necropolis Tyrant

Menace
Whenever another creature dies during your turn, put a +1/+1 counter on Vogar, Necropolis Tyrant.
When Vogar dies, draw a card for each +1/+1 counter on it.

Venomcrawler

Lifelink
Devourer of Souls — Whenever another creature dies, put a +1/+1 counter on Venomcrawler.

Hellkite Hatchling

Devour 1 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with that many +1/+1 counters on it.)
Hellkite Hatchling has flying and trample if it devoured a creature.

Dragon Broodmother

Flying
At the beginning of each upkeep, create a 1/1 red and green Dragon creature token with flying and devour 2. (As the token enters the battlefield, you may sacrifice any number of creatures. It enters the battlefield with twice that many +1/+1 counters on it.)

Caldera Hellion

Devour 1 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with that many +1/+1 counters on it.)
When Caldera Hellion enters the battlefield, it deals 3 damage to each creature.

Ravenous Gigantotherium

Devour 3 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with three times that many +1/+1 counters on it.)
When Ravenous Gigantotherium enters the battlefield, it deals X damage divided as you choose among up to X target creatures, where X is its power. Each of those creatures deals damage equal to its power to Ravenous Gigantotherium.

Moldervine Reclamation

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

Thromok the Insatiable

Devour X, where X is the number of creatures devoured this way (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with X +1/+1 counters on it for each of those creatures.)

Tar Fiend

Devour 2 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it.)
When Tar Fiend enters the battlefield, target player discards a card for each creature it devoured.

Skullmulcher

Devour 1 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with that many +1/+1 counters on it.)
When Skullmulcher enters the battlefield, draw a card for each creature it devoured.

Thunder-Thrash Elder

Devour 3 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with three times that many +1/+1 counters on it.)

Preyseizer Dragon

Flying
Devour 2 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it.)
Whenever Preyseizer Dragon attacks, it deals damage to any target equal to the number of +1/+1 counters on Preyseizer Dragon.

Bloodspore Thrinax

Devour 1 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with that many +1/+1 counters on it.)
Each other creature you control enters the battlefield with an additional X +1/+1 counters on it, where X is the number of +1/+1 counters on Bloodspore Thrinax.