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.

Whenever a creature you control deals combat damage to a player, you may draw a card.

{1}{U}, {T}: Creatures your opponents control attack this turn if able.

Target player draws X cards. Shuffle Blue Sun's Zenith into its owner's library.

When Breaching Leviathan enters the battlefield, if you cast it from your hand, tap all nonblue creatures. Those creatures don't untap during their controllers' next untap steps.

As Caged Sun enters the battlefield, choose a color.

Creatures you control of the chosen color get +1/+1.

Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Counter target spell.

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.

When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Coldsteel Heart enters the battlefield tapped.

As Coldsteel Heart enters the battlefield, choose a color.

{T}: Add one mana of the chosen color.

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

Whenever Colossal Whale attacks, you may exile target creature defending player controls until Colossal Whale leaves the battlefield. (That creature returns under its owner's control.)

Coral Atoll enters the battlefield tapped.

When Coral Atoll enters the battlefield, sacrifice it unless you return an untapped Island you control to its owner's hand.

{T}: Add {C}{U}.

Morph {U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

When Coral Trickster is turned face up, you may tap or untap target permanent.

Counter target spell.

Surge {3}{U}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)

Return all nonland permanents to their owners' hands. If this spell's surge cost was paid, create an 8/8 blue Octopus creature token.

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Return target nonland permanent you don't control to its owner's hand.

Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Deep-Sea Kraken can't be blocked.

Suspend 9--{2}{U} (Rather than cast this card from your hand, you may pay {2}{U} and exile it with nine time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, cast it without paying its mana cost. It has haste.)

Whenever an opponent casts a spell, if Deep-Sea Kraken is suspended, remove a time counter from it.

Flash

At the beginning of each player's draw step, that player draws an additional card.

Flash

Emerge {5}{U}{U} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)

When you cast this spell, tap up to four target permanents.

{U}{U}, {T}: Gain control of target legendary permanent. (This effect lasts indefinitely.)

Tap target untapped creature you control. If you do, add an amount of {C} equal to that creature's mana value.

Draw a card for each Island you control.

Defender, flying

Prevent all combat damage that would be dealt to and dealt by Fog Bank.

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.

Counter target spell.

When Great Whale enters the battlefield, untap up to seven lands.

Defender, flying

Prevent all combat damage that would be dealt to Guard Gomazoa.

Halimar Depths enters the battlefield tapped.

When Halimar Depths enters the battlefield, look at the top three cards of your library, then put them back in any order.

{T}: Add {U}.

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Enchant creature, land, or planeswalker

Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

Flash

At the beginning of your end step, draw seven cards.

Each opponent's maximum hand size is reduced by seven.

Flying

Creatures you control have "Whenever this creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability."

Creatures with power less than the number of Islands you control can't block Kraken of the Straits.

If Leyline of Anticipation is in your opening hand, you may begin the game with it on the battlefield.

You may cast spells as though they had flash.

Whenever Lorthos, the Tidemaker attacks, you may pay {8}. If you do, tap up to eight target permanents. Those permanents don't untap during their controllers' next untap steps.

When Man-o'-War enters the battlefield, return target creature to its owner's hand.

Protection from red

Elemental creatures you control get +1/+1.

When Master of Waves enters the battlefield, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

{T}: Add {C}.

{1}, {T}, Sacrifice Mind Stone: Draw a card.

Flying

When Mulldrifter enters the battlefield, draw two cards.

Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Myriad Landscape enters the battlefield tapped.

{T}: Add {C}.

{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

This spell can't be countered.

You have no maximum hand size.

Whenever an opponent casts a noncreature spell, draw a card.

Discard three cards: Exile Nezahal, Primal Tide. Return it to the battlefield tapped under its owner's control at the beginning of the next end step.

{T}: Add {C}.

{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

At the beginning of your upkeep, you may look at the top card of your library. If it's a creature card, you may reveal it and put a quest counter on Quest for Ula's Temple.

At the beginning of each end step, if there are three or more quest counters on Quest for Ula's Temple, you may put a Kraken, Leviathan, Octopus, or Serpent creature card from your hand onto the battlefield.

At the beginning of each player's upkeep, that player puts a flood counter on target non-Island land they control of their choice. That land is an Island for as long as it has a flood counter on it.

At the beginning of each end step, if all lands on the battlefield are Islands, remove all flood counters from them.

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

When Reef Worm dies, create a 3/3 blue Fish creature token with "When this creature dies, create a 6/6 blue Whale creature token with 'When this creature dies, create a 9/9 blue Kraken creature token.'"

You have no maximum hand size.

{T}: Add {C}.

Counter target spell. Untap up to four lands.

Kicker {5} (You may pay an additional {5} as you cast this spell.)

Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Blue spells you cast cost {1} less to cast.

When Scourge of Fleets enters the battlefield, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

{1}: Look at the top three cards of your library, then put them back in any order.

{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

{6}{U}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)

When Shipbreaker Kraken becomes monstrous, tap up to four target creatures. Those creatures don't untap during their controllers' untap steps for as long as you control Shipbreaker Kraken.

Sky Diamond enters the battlefield tapped.

{T}: Add {U}.

Skyline Cascade enters the battlefield tapped.

When Skyline Cascade enters the battlefield, target creature an opponent controls doesn't untap during its controller's next untap step.

{T}: Add {U}.

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)

When Slinn Voda, the Rising Deep enters the battlefield, if it was kicked, return all creatures to their owners' hands except for Merfolk, Krakens, Leviathans, Octopuses, and Serpents.

{T}: Add {C}{C}.

Counter target spell. Create X Treasure tokens, where X is that spell's mana value. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Hexproof

Lieutenant -- As long as you control your commander, Stormsurge Kraken gets +2/+2 and has "Whenever Stormsurge Kraken becomes blocked, you may draw two cards."

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.

Equipped creature gets +1/+1.

Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Equip {2}

Whenever you cast an instant or sorcery spell, create a 2/2 blue Drake creature token with flying.

{T}: Add {C}{C}. Activate only if you control five or more lands.

Take an extra turn after this one. Exile Temporal Mastery.

Miracle {1}{U} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

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

Whenever Thada Adel, Acquisitor deals combat damage to a player, search that player's library for an artifact card and exile it. Then that player shuffles. Until end of turn, you may play that card.

Indestructible

As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

At the beginning of your upkeep, scry 1.

{1}{U}: Target creature you control can't be blocked this turn.

Tromokratis has hexproof unless it's attacking or blocking.

Tromokratis can't be blocked unless all creatures defending player controls block it. (If any creature that player controls doesn't block this creature, it can't be blocked.)

Flash

When Venser, Shaper Savant enters the battlefield, return target spell or permanent to its owner's hand.

Whenever a permanent you control becomes untapped, Wake Thrasher gets +1/+1 until end of turn.

Return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.

Flying

As long as Wonder is in your graveyard and you control an Island, creatures you control have flying.