Manahive

“Wave Elemental” is a blue creature that taps all creatures without flying when it enters the battlefield.
Blue cards with similar effects include:

• “Aethersnipe” (bounces a creature on ETB)
• “Floodtide Serpent” (returns lands when attacking, has synergies with bounce)
• “Ætherize” (returns all attacking creatures to owners' hands)
• “Flood of Tears” (returns all nonland permanents to hand)

Reason: These blue cards interact with multiple creatures or tap/bounce many creatures, like “Wave Elemental.”