Chittering Host

Haste
Menace (This creature can't be blocked except by two or more creatures.)
When this creature enters, other creatures you control get +1/+0 and gain menace until end of turn.

Yarok, the Desecrated

Deathtouch, lifelink
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Archfiend of the Dross

Flying
This creature enters with four oil counters on it.
At the beginning of your upkeep, remove an oil counter from this creature. Then if it has no oil counters on it, you lose the game.
Whenever a creature an opponent controls dies, its controller loses 2 life.

Biting-Palm Ninja

Ninjutsu {2}{B}
This creature enters with a menace counter on it.
Whenever this creature deals combat damage to a player, you may remove a menace counter from it. When you do, that player reveals their hand and you choose a nonland card from it. Exile that card.

Grave Titan

Deathtouch
Whenever this creature enters or attacks, create two 2/2 black Zombie creature tokens.

Fleshbag Marauder

When this creature enters, each player sacrifices a creature of their choice.

Anthroplasm

This creature enters with two +1/+1 counters on it.
{X}, {T}: Remove all +1/+1 counters from this creature and put X +1/+1 counters on it.

Faceless Butcher

When this creature enters, exile another target creature.
When this creature leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Necrosquito

Flying
This creature enters with two oil counters on it.
This creature gets +1/+1 for each oil counter on it.
Whenever another creature or artifact you control is put into a graveyard from the battlefield, put an oil counter on this creature.

Falcon Abomination

Flying
When this creature enters, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Enlightened Maniac

When this creature enters, create a 3/2 colorless Eldrazi Horror creature token.

Phyrexian Gargantua

When this creature enters, you draw two cards and you lose 2 life.

Mind Maggots

When this creature enters, discard any number of creature cards. For each card discarded this way, put two +1/+1 counters on this creature.

Brain Maggot

When this creature enters, target opponent reveals their hand and you choose a nonland card from it. Exile that card until this creature leaves the battlefield.

Phyrexian Rager

When this creature enters, you draw a card and you lose 1 life.

Rank and File

When this creature enters, green creatures get -1/-1 until end of turn.

Oil-Gorger Troll

When this creature enters, you gain 3 life. Then if you control a permanent with an oil counter on it, draw a card.

Plaguecrafter

When this creature enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Sibsig Host

When this creature enters, each player mills three cards.

The Master, Transcendent

When The Master enters, target player gets two rad counters.
{T}: Put target creature card in a graveyard that was milled this turn onto the battlefield under your control. It's a green Mutant with base power and toughness 3/3. (It loses its other colors and creature types.)

Wormfang Turtle

When this creature enters, exile a land you control.
When this creature leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Fear of Impostors

Flash
When this creature enters, counter target spell. Its controller manifests dread. (That player looks at the top two cards of their library, then puts one onto the battlefield face down as a 2/2 creature and the other into their graveyard. If it's a creature card, it can be turned face up any time for its mana cost.)

Endless One

This creature enters with X +1/+1 counters on it.

Foul Emissary

When this creature enters, look at the top four cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.
When you sacrifice this creature while casting a spell with emerge, create a 3/2 colorless Eldrazi Horror creature token.

Broodspinner

Reach
When this creature enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
{4}{B}{G}, {T}, Sacrifice this creature: Create a number of 1/1 black and green Insect creature tokens with flying equal to the number of card types among cards in your graveyard.