Stormbound Geist

Flying
This creature can block only creatures with flying.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Merfolk Spy

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever this creature deals combat damage to a player, that player reveals a card at random from their hand.

Spreading Seas

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

Annul

Counter target artifact or enchantment spell.

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.

Counterspell

Island

Bind the Monster

Enchant creature
When this Aura enters, tap enchanted creature. It deals damage to you equal to its power.
Enchanted creature doesn't untap during its controller's untap step.

Coral Barrier

Defender (This creature can't attack.)
When this creature enters, create a 1/1 blue Squid creature token with islandwalk. (It can't be blocked as long as defending player controls an Island.)

Squid

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

Frantic Inventory

Draw a card, then draw cards equal to the number of cards named Frantic Inventory in your graveyard.

Echoing Truth

Return target nonland permanent and all other permanents with the same name as that permanent to their owners' hands.

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Haunted Fengraf

{T}: Add {C}.
{3}, {T}, Sacrifice this land: Return a creature card at random from your graveyard to your hand.

Tormod's Crypt

{T}, Sacrifice this artifact: Exile target player's graveyard.

Dispel

Harbor Serpent

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
This creature can't attack unless there are five or more Islands on the battlefield.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.