Stormtide Leviathan

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.

Colossal Majesty

At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.

Explore

You may play an additional land this turn.
Draw a card.

Regrowth

Return target card from your graveyard to your hand.

Counterspell

Charix, the Raging Isle

Spells your opponents cast that target Charix, the Raging Isle cost {2} more to cast.
{3}: Charix gets +X/-X until end of turn, where X is the number of Islands you control.

Quick Study

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Kraken Hatchling

Woodland Stream

Woodland Stream enters tapped.
{T}: Add {G} or {U}.

Nadir Kraken

Whenever you draw a card, you may pay {1}. If you do, put a +1/+1 counter on Nadir Kraken and create a 1/1 blue Tentacle creature token.

Tangled Islet

({T}: Add {G} or {U}.)
Tangled Islet enters tapped.

Quicksilver Amulet

{4}, {T}: You may put a creature card from your hand onto the battlefield.

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Forest

Murkfiend Liege

Other green creatures you control get +1/+1.
Other blue creatures you control get +1/+1.
Untap all green and/or blue creatures you control during each other player's untap step.

Island

Serpent of Yawning Depths

Krakens, Leviathans, Octopuses, and Serpents you control can't be blocked except by Krakens, Leviathans, Octopuses, and Serpents.