Nature's Rhythm

Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.
Harmonize {X}{G}{G}{G}{G} (You may cast this card from your graveyard for its harmonize cost. You may tap a creature you control to reduce that cost by an amount of generic mana equal to its power. Then exile this spell.)

Drumbellower

Flying
Untap all creatures you control during each other player's untap step.

Chord of Calling

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

White Plume Adventurer

When this creature enters, you take the initiative.
At the beginning of each opponent's upkeep, untap a creature you control. If you've completed a dungeon, untap all creatures you control instead.

Emmara, Soul of the Accord

Whenever Emmara becomes tapped, create a 1/1 white Soldier creature token with lifelink.