Wind Strider

Flash (You may cast this spell any time you could cast an instant.)
Flying

Spreading Seas

Enchant land
When this Aura enters, draw a card.
Enchanted land is an Island.

Reef Shaman

{T}: Target land becomes the basic land type of your choice until end of turn.

Counterspell

Aquitect's Will

Put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. If you control a Merfolk, draw a card.

Dive Down

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Rootwater Commando

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Stonybrook Banneret

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Merfolk spells and Wizard spells you cast cost {1} less to cast.

Ice Over

Enchant artifact or creature
Enchanted permanent doesn't untap during its controller's untap step.

Island

Halimar Wavewatch

Level up {2} ({2}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-4
0/6
LEVEL 5+
6/6
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Mist-Cloaked Herald

Enclave Elite

Multikicker {1}{U} (You may pay an additional {1}{U} any number of times as you cast this spell.)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
This creature enters with a +1/+1 counter on it for each time it was kicked.