Eternal Witness

When this creature enters, you may return target card from your graveyard to your hand.

Parasitic Strix

Flying
When this creature enters, if you control a black permanent, target player loses 2 life and you gain 2 life.

Baleful Strix

Flying, deathtouch
When this creature enters, draw a card.

Blue Sun's Zenith

Target player draws X cards. Shuffle Blue Sun's Zenith into its owner's library.

Cavern Harpy

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

Dosan the Falling Leaf

Players can cast spells only during their own turns.

Palinchron

Flying
When this creature enters, untap up to seven lands.
{2}{U}{U}: Return this creature to its owner's hand.

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.

Echo of Eons

Each player shuffles their hand and graveyard into their library, then draws seven cards.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Cultivate

Dream Stalker

When this creature enters, return a permanent you control to its owner's hand.

Aluren

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