Wirewood Symbiote

Return an Elf you control to its owner's hand: Untap target creature. Activate only once each turn.

Hyrax Tower Scout

When this creature enters, untap target creature.

Captain of the Mists

Whenever another Human you control enters, untap this creature.
{1}{U}, {T}: You may tap or untap target permanent.

Cacophodon

Enrage — Whenever this creature is dealt damage, untap target permanent.

Quirion Ranger

Return a Forest you control to its owner's hand: Untap target creature. Activate only once each turn.

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.

Chakram Retriever

Partner with Chakram Slinger (When this creature enters, target player may put Chakram Slinger into their hand from their library, then shuffle.)
Whenever you cast a spell during your turn, untap target creature.

Mirran Spy

Flying
Whenever you cast an artifact spell, you may untap target creature.

Corridor Monitor

When this creature enters, untap target artifact or creature you control.

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.

Civic Gardener

Whenever this creature attacks, untap target creature or land.

Deceiver Exarch

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, choose one —
• Untap target permanent you control.
• Tap target permanent an opponent controls.