Meandering Towershell

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Meandering Towershell attacks, exile it. Return it to the battlefield under your control tapped and attacking at the beginning of the declare attackers step on your next turn.

Choke

Islands don't untap during their controllers' untap steps.

Typhoon

Typhoon deals damage to each opponent equal to the number of Islands that player controls.

Curse of Marit Lage

When Curse of Marit Lage enters, tap all Islands.
Islands don't untap during their controllers' untap steps.

Tsunami

Boiling Seas

Scald

Whenever a player taps an Island for mana, Scald deals 1 damage to that player.

Monsoon

At the beginning of each player's end step, tap all untapped Islands that player controls and Monsoon deals X damage to the player, where X is the number of Islands tapped this way.

Saskia the Unyielding

Vigilance, haste
As Saskia the Unyielding enters, choose a player.
Whenever a creature you control deals combat damage to a player, it deals that much damage to the chosen player.

Boil

Thoughtleech

Whenever an Island an opponent controls becomes tapped, you may gain 1 life.

Carpet of Flowers

At the beginning of each of your main phases, if you haven't added mana with this ability this turn, you may add X mana of any one color, where X is the number of Islands target opponent controls.