Rhet-Crop Spearmaster

You may exert Rhet-Crop Spearmaster as it attacks. When you do, it gets +1/+0 and gains first strike until end of turn. (An exerted creature won't untap during your next untap step.)

Freed from the Real

Enchant creature
{U}: Tap enchanted creature.
{U}: Untap enchanted creature.

Battle Screech

Create two 1/1 white Bird creature tokens with flying.
Flashback—Tap three untapped white creatures you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Plains

Dauntless Aven

Flying
Whenever Dauntless Aven attacks, untap target creature you control.

Tranquil Cove

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {U}.

Tah-Crop Elite

Flying
You may exert Tah-Crop Elite as it attacks. When you do, creatures you control get +1/+1 until end of turn. (An exerted creature won't untap during your next untap step.)

Island

Dramatic Reversal

Untap all nonland permanents you control.

Militia Rallier

Militia Rallier can't attack alone.
Whenever Militia Rallier attacks, untap target creature.

Gust Walker

You may exert Gust Walker as it attacks. When you do, it gets +1/+1 and gains flying until end of turn. (An exerted creature won't untap during your next untap step.)

Beacon Hawk

Flying
Whenever Beacon Hawk deals combat damage to a player, you may untap target creature.
{W}: Beacon Hawk gets +0/+1 until end of turn.

Oketra's Avenger

You may exert Oketra's Avenger as it attacks. When you do, prevent all combat damage that would be dealt to it this turn. (An exerted creature won't untap during your next untap step.)