Clone

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

Vodalian Knights

First strike
This creature can't attack unless defending player controls an Island.
When you control no Islands, sacrifice this creature.
{U}: This creature gains flying until end of turn.

Control Magic

Enchant creature
You control enchanted creature.

Juggernaut

This creature attacks each combat if able.
This creature can't be blocked by Walls.

River Merfolk

{U}: This creature gains mountainwalk until end of turn. (It can't be blocked as long as defending player controls a Mountain.)

Dance of Many

When this enchantment enters, create a token that's a copy of target nontoken creature.
When this enchantment leaves the battlefield, exile the token.
When the token leaves the battlefield, sacrifice this enchantment.
At the beginning of your upkeep, sacrifice this enchantment unless you pay {U}{U}.

Island

Aeolipile

{1}, {T}, Sacrifice this artifact: It deals 2 damage to any target.

Dandân

This creature can't attack unless defending player controls an Island.
When you control no Islands, sacrifice this creature.

Merfolk of the Pearl Trident

Braingeyser

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Su-Chi

When this creature dies, add {C}{C}{C}{C}.

Lord of Atlantis

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

Unsummon

Return target creature to its owner's hand.

Boomerang

Return target permanent 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.

Psionic Blast

Psionic Blast deals 4 damage to any target and 2 damage to you.

Serendib Efreet

Flying
At the beginning of your upkeep, this creature deals 1 damage to you.

Counterspell

Mishra's Factory

{T}: Add {C}.
{1}: This land becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Seasinger

When you control no Islands, sacrifice this creature.
You may choose not to untap this creature during your untap step.
{T}: Gain control of target creature whose controller controls an Island for as long as you control this creature and this creature remains tapped.

Phantasmal Terrain

Enchant land
As this Aura enters, choose a basic land type.
Enchanted land is the chosen type.

Serendib Djinn

Flying
At the beginning of your upkeep, sacrifice a land. If you sacrifice an Island this way, this creature deals 3 damage to you.
When you control no lands, sacrifice this creature.