Rimewind Taskmage

{1}, {T}: You may tap or untap target permanent. Activate only if you control four or more snow permanents.

Derevi, Empyrial Tactician

Flying
When Derevi, Empyrial Tactician enters and whenever a creature you control deals combat damage to a player, you may tap or untap target permanent.
{1}{G}{W}{U}: Put Derevi onto the battlefield from the command zone.

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.

Blossom Dryad

Patron of the Orochi

Snake offering (You may cast this spell any time you could cast an instant by sacrificing a Snake and paying the difference in mana costs between this and the sacrificed Snake. Mana cost includes color.)
{T}: Untap all Forests and all green creatures. Activate only once each turn.

Captain of the Mists

Whenever another Human you control enters, untap Captain of the Mists.
{1}{U}, {T}: You may tap or untap target permanent.

Hokori, Dust Drinker

Lands don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player untaps a land they control.

Cacophodon

Enrage — Whenever Cacophodon is dealt damage, untap target permanent.

Tidal Force

At the beginning of each upkeep, you may tap or untap target permanent.

Juniper Order Druid

Voyaging Satyr

Tidewater Minion

Defender (This creature can't attack.)
{4}: Tidewater Minion loses defender until end of turn.
{T}: Untap target permanent.

Vizier of Tumbling Sands

{T}: Untap another target permanent.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)
When you cycle Vizier of Tumbling Sands, untap target permanent.

Ley Druid

Kiora, Behemoth Beckoner

Whenever a creature you control with power 4 or greater enters, draw a card.
−1: Untap target permanent.

Hope Tender

{1}, {T}: Untap target land.
{1}, {T}, Exert Hope Tender: Untap two target lands. (An exerted creature won't untap during your next untap step.)

Oboro Breezecaller

Flying
{2}, Return a land you control to its owner's hand: Untap target land.

Deserted Temple

{T}: Add {C}.
{1}, {T}: Untap target land.

Arbor Elf

Krosan Restorer

{T}: Untap target land.
Threshold — {T}: Untap up to three target lands. Activate only if seven or more cards are in your graveyard.

Stone-Seeder Hierophant

Landfall — Whenever a land you control enters, untap Stone-Seeder Hierophant.
{T}: Untap target land.