Mahamoti Djinn

Flying (This creature can't be blocked except by creatures with flying or reach.)

Lord of Atlantis

Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Control Magic

Enchant creature
You control enchanted creature.

Merfolk of the Pearl Trident

Sol Ring

Island

Clone

You may have Clone enter as a copy of any creature on the battlefield.

Counterspell

Unsummon

Return target creature to its owner's hand.

Unstable Mutation

Enchant creature
Enchanted creature gets +3/+3.
At the beginning of the upkeep of enchanted creature's controller, put a -1/-1 counter on that creature.

Phantasmal Terrain

Enchant land
As Phantasmal Terrain enters, choose a basic land type.
Enchanted land is the chosen type.