Acererak the Archlich

When Acererak the Archlich enters the battlefield, if you haven't completed Tomb of Annihilation, return Acererak the Archlich to its owner's hand and venture into the dungeon.
Whenever Acererak the Archlich attacks, for each opponent, you create a 2/2 black Zombie creature token unless that player sacrifices a creature.

Elvish Visionary

When Elvish Visionary enters the battlefield, draw a card.

Generous Stray

When Generous Stray enters the battlefield, draw a card.

Multani's Acolyte

Echo {G}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Multani's Acolyte enters the battlefield, draw a card.

Nantuko Shaman

When Nantuko Shaman enters the battlefield, if you control no tapped lands, draw a card.
Suspend 1—{2}{G}{G} (Rather than cast this card from your hand, you may pay {2}{G}{G} and exile it with a time counter on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)

Merchant of Secrets

When Merchant of Secrets enters the battlefield, draw a card.

Stonecloaker

Flash
Flying
When Stonecloaker enters the battlefield, return a creature you control to its owner's hand.
When Stonecloaker enters the battlefield, exile target card from a graveyard.

Inspiring Overseer

Flying
When Inspiring Overseer enters the battlefield, you gain 1 life and draw a card.

Llanowar Visionary

When Llanowar Visionary enters the battlefield, draw a card.
{T}: Add {G}.

Priest of Ancient Lore

When Priest of Ancient Lore enters the battlefield, you gain 1 life and draw a card.

Aluren

Any player may cast creature spells with mana value 3 or less without paying their mana costs and as though they had flash.

Cavern Harpy

Flying
When Cavern Harpy enters the battlefield, return a blue or black creature you control to its owner's hand.
Pay 1 life: Return Cavern Harpy to its owner's hand.

Skyscanner

Flying
When Skyscanner enters the battlefield, draw a card.

Baleful Strix

Flying, deathtouch
When Baleful Strix enters the battlefield, draw a card.

Ice-Fang Coatl

Flash
Flying
When Ice-Fang Coatl enters the battlefield, draw a card.
Ice-Fang Coatl has deathtouch as long as you control at least three other snow permanents.

Parasitic Strix

Flying
When Parasitic Strix enters the battlefield, if you control a black permanent, target player loses 2 life and you gain 2 life.