Fylamarid

Flying
Fylamarid can't be blocked by blue creatures.
{U}: Target creature becomes blue until end of turn.

Cold-Water Snapper

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Purple-Crystal Crab

When Purple-Crystal Crab dies, draw a card.

Bronze Walrus

When Bronze Walrus enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)
{T}: Add one mana of any color.

Red Herring

{1}{U}: Exchange Red Herring from your hand with a permanent you control on the battlefield or a spell you control on the stack. If that permanent or spell was the target of a spell or ability, change that target to Red Herring.

Daggermaw Megalodon

Vigilance
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Reef Worm

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.'"

Electric Eel

When Electric Eel enters, it deals 1 damage to you.
{R}{R}: Electric Eel gets +2/+0 until end of turn and deals 1 damage to you.

Jackdaw

Whenever Jackdaw deals combat damage to a player, you may discard your hand. If you do, draw a card for each artifact you control.
Crew 3

Sinister Starfish

{T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Oneirophage

Flying
Whenever you draw a card, put a +1/+1 counter on Oneirophage.

Cement Shoes

Equipped creature gets +3/+3 and has "At the beginning of your end step, tap this creature."
Equipped creature doesn't untap during its controller's untap step.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Horseshoe Crab

Narwhal

Sigiled Starfish

{T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Shipbreaker Kraken

{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.

Coral Eel

Clinging Anemones

Defender
Evolve (Whenever a creature enters under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Giant Octopus

Maeve, Insidious Singer

{2}{U}: Goad target creature. Whenever that creature attacks one of your opponents this turn, you draw a card. (A goaded creature attacks each combat if able and attacks a player other than you if able, until your next turn.)

Frost Fair Lure Fish

When Frost Fair Lure Fish enters, create two 1/1 blue Fish creature tokens and create two tapped Treasure tokens.
Fish you control have haste and can't be blocked by Humans.
Foretell {3}{U}{R}

Octoprophet

When Octoprophet enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Chasm Skulker

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.)

Ancient Carp

Pygmy Hippo

Whenever Pygmy Hippo attacks and isn't blocked, you may have defending player activate a mana ability of each land they control and lose all unspent mana. If you do, Pygmy Hippo assigns no combat damage this turn and at the beginning of your next main phase this turn, you add an amount of {C} equal to the amount of mana that player lost this way.

Adrestia

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Adrestia attacks, if an Assassin crewed it this turn, draw a card. Adrestia becomes an Assassin in addition to its other types until end of turn.
Crew 1

Wormhole Serpent

{3}{U}: Target creature can't be blocked this turn.

Spined Megalodon

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever Spined Megalodon attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Denizen of the Deep

When Denizen of the Deep enters, return each other creature you control to its owner's hand.

Gulf Squid

When Gulf Squid enters, tap all lands target player controls.

Red Death, Shipwrecker

Alluring Eyes — {T}: Goad target creature an opponent controls. That player draws a card. You add {R}. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Frilled Sea Serpent

{5}{U}{U}: Frilled Sea Serpent can't be blocked this turn.

Fish

Trench Behemoth

Return a land you control to its owner's hand: Untap Trench Behemoth. It gains hexproof until end of turn.
Landfall — Whenever a land you control enters, target creature an opponent controls attacks during its controller's next combat phase if able.

Tolarian Kraken

Whenever you draw a card, you may pay {1}. When you do, you may tap or untap target creature.

Tidal Barracuda

Any player may cast spells as though they had flash.
Your opponents can't cast spells during your turn.

Armored Whirl Turtle

Colossal Whale

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.)

Kraken Hatchling

Mulldrifter

Flying
When Mulldrifter enters, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Deep Spawn

Trample
At the beginning of your upkeep, sacrifice Deep Spawn unless you mill two cards.
{U}: Deep Spawn gains shroud until end of turn and doesn't untap during your next untap step. Tap Deep Spawn. (A creature with shroud can't be the target of spells or abilities.)

Kraken of the Straits

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Ancient Crab

Canyon Crab

{1}{U}: Canyon Crab gets +2/-2 until end of turn.
At the beginning of your end step, if you haven't cast a spell from your hand this turn, draw a card, then discard a card.

Moat Piranhas

Augur of Bolas

When Augur of Bolas enters, look at the top three cards of your library. You may reveal an instant or sorcery card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Snapping Voidcraw

Devoid (This card has no color.)
{T}: Add {C}{C}.
{3}{C}, {T}: Draw a card.

Silburlind Snapper

Silburlind Snapper can't attack unless you've cast a noncreature spell this turn.

Waker of Waves

Creatures your opponents control get -1/-0.
{1}{U}, Discard Waker of Waves: Look at the top two cards of your library. Put one of them into your hand and the other into your graveyard.

Fishing Pole

Equipped creature has "{1}, {T}, Tap Fishing Pole: Put a bait counter on Fishing Pole."
Whenever equipped creature becomes untapped, remove a bait counter from this Equipment. If you do, create a 1/1 blue Fish creature token.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Man-o'-War

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

Killer Whale

{U}: Killer Whale gains flying until end of turn.

Thunderous Snapper

Whenever you cast a spell with mana value 5 or greater, draw a card.

Blufferfish

{3}{U}: An opponent tells you a statement about themselves and secretly notes whether it's true or false. You guess which it is. If you guessed correctly, Blufferfish gets +2/+0 and can't be blocked this turn.

Haste
Red Herring attacks each combat if able.
{2}, Sacrifice Red Herring: Draw a card.

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Great Whale

When Great Whale enters, untap up to seven lands.

Junk

{T}, Sacrifice this artifact: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.

Segovian Leviathan

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

Pursued Whale

When Pursued Whale enters, each opponent creates a 1/1 red Pirate creature token with "This creature can't block" and "Creatures you control attack each combat if able."
Spells your opponents cast that target Pursued Whale cost {3} more to cast.

Jace's Mindseeker

Flying
When Jace's Mindseeker enters, target opponent mills five cards. You may cast an instant or sorcery spell from among them without paying its mana cost.

Trench Gorger

Trample
When Trench Gorger enters, you may search your library for any number of land cards, exile them, then shuffle. If you do, Trench Gorger has base power and base toughness each equal to the number of cards exiled this way.

Stinging Lionfish

Whenever you cast your first spell during each opponent's turn, you may tap or untap target nonland permanent.

Sand Squid

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
You may choose not to untap Sand Squid during your untap step.
{T}: Tap target creature. That creature doesn't untap during its controller's untap step for as long as Sand Squid remains tapped.