Disciple of the Ring

{1}, Exile an instant or sorcery card from your graveyard: Choose one —
• Counter target noncreature spell unless its controller pays {2}.
• This creature gets +1/+1 until end of turn.
• Tap target creature.
• Untap target creature.

Mnemonic Wall

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

Great Oak Guardian

Flash (You may cast this spell any time you could cast an instant.)
Reach
When this creature enters, creatures target player controls get +2/+2 until end of turn. Untap them.

Breaching Hippocamp

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, untap another target creature you control.

Bounding Krasis

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, you may tap or untap target creature.

Craterhoof Behemoth

Haste
When this creature enters, creatures you control gain trample and get +X/+X until end of turn, where X is the number of creatures you control.

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Spellseeker

When this creature enters, you may search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

Dramatic Reversal

Untap all nonland permanents you control.

Woodland Bellower

When this creature enters, you may search your library for a nonlegendary green creature card with mana value 3 or less, put it onto the battlefield, then shuffle.

Pestermite

Flash
Flying
When this creature enters, you may tap or untap target permanent.

Prime Speaker Vannifar

{T}, Sacrifice another creature: Search your library for a creature card with mana value equal to 1 plus the sacrificed creature's mana value, put that card onto the battlefield, then shuffle. Activate only as a sorcery.

Archaeomancer

When this creature enters, return target instant or sorcery card from your graveyard to your hand.