Pirate Ship

Pirate Ship can't attack unless defending player controls an Island.
{T}: Pirate Ship deals 1 damage to any target.
When you control no Islands, sacrifice Pirate Ship.

Conservator

{3}, {T}: Prevent the next 2 damage that would be dealt to you this turn.

Phantom Monster

Rod of Ruin

{3}, {T}: Rod of Ruin deals 1 damage to any target.

Psychic Venom

Enchant land
Whenever enchanted land becomes tapped, Psychic Venom deals 2 damage to that land's controller.

Water Elemental

Island Fish Jasconius

Island Fish Jasconius doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {U}{U}{U}. If you do, untap Island Fish Jasconius.
Island Fish Jasconius can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Island Fish Jasconius.

Dandân

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

Island

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.

Phantasmal Terrain

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

Sea Serpent

Sea Serpent can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Sea Serpent.