
Aerial Formation | Instant | | Strive — This spell costs {2}{U} more to cast for each target beyond the first.
Any number of target creatures each get +1/+1 and gain flying until end of turn. | Zack Stella

Dakra Mystic | Creature | Merfolk Wizard | {U}, {T}: Each player reveals the top card of their library. You may put the revealed cards into their owners' graveyards. If you don't, each player draws a card. | Wesley Burt

Hypnotic Siren | Enchantment Creature | Siren | Bestow {5}{U}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying
You control enchanted creature.
Enchanted creature gets +1/+1 and has flying. | James Ryman

Kiora's Dismissal | Instant | | Strive — This spell costs {U} more to cast for each target beyond the first.
Return any number of target enchantments to their owners' hands. | Mathias Kollros

Thassa's Ire | Enchantment | | {3}{U}: You may tap or untap target creature. | Chris Rahn

Triton Shorestalker | Creature | Merfolk Rogue | Triton Shorestalker can't be blocked. | Svetlin Velinov