Floodwaters

Return up to two target creatures to their owners' hands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Water Servant

{U}: This creature gets +1/-1 until end of turn.
{U}: This creature gets -1/+1 until end of turn.

Wave-Wing Elemental

Flying
Landfall — Whenever a land you control enters, this creature gets +2/+2 until end of turn.

Bubble Up

Put target instant or sorcery card from your graveyard on top of your library. (Then exile this card. You may cast the creature later from exile.)

Aquatic Alchemist

Whenever you cast your first instant or sorcery spell each turn, this creature gets +2/+0 until end of turn.

Aquatic Alchemist // Bubble Up

Sea God's Scorn

Return up to three target creatures and/or enchantments to their owners' hands.

Lonely Sandbar

This land enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Rain of Revelation

Thassa's Devourer

Constellation — Whenever this creature or another enchantment you control enters, target player mills two cards.

Clutch of Currents

Return target creature to its owner's hand.
Awaken 3—{4}{U} (If you cast this spell for {4}{U}, also put three +1/+1 counters on target land you control and it becomes a 0/0 Elemental creature with haste. It's still a land.)

Displacement Wave

Return all nonland permanents with mana value X or less to their owners' hands.

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Griptide

Put target creature on top of its owner's library.

Risen Riptide

Whenever you cast a kicked spell, this creature has base power and toughness 5/5 until end of turn.

The Myriad Pools

(Transforms from The Everflowing Well.)
{T}: Add {U}.
Whenever you cast a permanent spell using mana produced by The Myriad Pools, up to one other target permanent you control becomes a copy of that spell until end of turn.

The Everflowing Well

When The Everflowing Well enters, mill two cards, then draw two cards.
Descend 8 — At the beginning of your upkeep, if there are eight or more permanent cards in your graveyard, transform The Everflowing Well.

The Everflowing Well // The Myriad Pools

Flow of Knowledge

Draw a card for each Island you control, then discard two cards.

Amphibian Downpour

Flash
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies. Copies become tokens.)
Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1.

Cavalier of Gales

Flying
When this creature enters, draw three cards, then put two cards from your hand on top of your library in any order.
When this creature dies, shuffle it into its owner's library, then 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.)

Splashy Spellcaster

Whenever you cast an instant or sorcery spell, create a Sorcerer Role token attached to up to one other target creature you control. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1 and has "Whenever this creature attacks, scry 1.")

Vaporkin

Flying
This creature can block only creatures with flying.

Vortex Elemental

{U}: Put this creature and each creature blocking or blocked by it on top of their owners' libraries, then those players shuffle.
{3}{U}{U}: Target creature blocks this creature this turn if able.

Rushing River

Kicker—Sacrifice a land. (You may sacrifice a land in addition to any other costs as you cast this spell.)
Return target nonland permanent to its owner's hand. If this spell was kicked, return another target nonland permanent to its owner's hand.

Consuming Tide

Each player chooses a nonland permanent they control. Return all nonland permanents not chosen this way to their owners' hands. Then you draw a card for each opponent who has more cards in their hand than you.

High Seas

Red creature spells and green creature spells cost {1} more to cast.

Chakram Retriever

Partner with Chakram Slinger (When this creature enters, target player may put Chakram Slinger into their hand from their library, then shuffle.)
Whenever you cast a spell during your turn, untap target creature.

Crashing Tide

This spell has flash as long as you control a Merfolk.
Return target creature to its owner's hand.
Draw a card.

Octavia, Living Thesis

This spell costs {8} less to cast if you have eight or more instant and/or sorcery cards in your graveyard.
Ward {8}
Magecraft — Whenever you cast or copy an instant or sorcery spell, target creature has base power and toughness 8/8 until end of turn.

Soul of the Rapids

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

Floating-Dream Zubera

When this creature dies, draw a card for each Zubera that died this turn.

Rushing-Tide Zubera

When this creature dies, if 4 or more damage was dealt to it this turn, draw three cards.

Mnemonic Deluge

Exile target instant or sorcery card from a graveyard. Copy that card three times. You may cast the copies without paying their mana costs. Exile Mnemonic Deluge.

Waterspout Elemental

Kicker {U} (You may pay an additional {U} as you cast this spell.)
Flying
When this creature enters, if it was kicked, return all other creatures to their owners' hands and you skip your next turn.

Water Wings

Until end of turn, target creature you control has base power and toughness 4/4 and gains flying and hexproof. (It can't be the target of spells or abilities your opponents control.)

Yarok's Wavecrasher

When this creature enters, return another creature you control to its owner's hand.

Perilous Research

Draw two cards, then sacrifice a permanent.

Waterknot

Enchant creature
When this Aura enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Deluge

Dreadwaters

Target player mills X cards, where X is the number of lands you control.

Submerge

If an opponent controls a Forest and you control an Island, you may cast this spell without paying its mana cost.
Put target creature on top of its owner's library.

High Tide

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

Fathom Seer

Morph—Return two Islands you control to their owner's hand. (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 this creature is turned face up, draw two cards.

Engulf the Shore

Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.

River's Rebuke

Return all nonland permanents target player controls to their owner's hand.

Inundate

Return all nonblue creatures to their owners' hands.

Flash Flood

Choose one —
• Destroy target red permanent.
• Return target Mountain to its owner's hand.

Castle Vantress

Castle Vantress enters tapped unless you control an Island.
{T}: Add {U}.
{2}{U}{U}, {T}: Scry 2.

Aquamoeba

Discard a card: Switch this creature's power and toughness until end of turn.

Tidal Bore

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
You may tap or untap target creature.

Tidewalker

This creature enters with a time counter on it for each Island you control.
Vanishing (At the beginning of your upkeep, remove a time counter from this creature. When the last is removed, sacrifice it.)
Tidewalker's power and toughness are each equal to the number of time counters on it.

Waterwhirl

Return up to two target creatures to their owners' hands.

Gush

You may return two Islands you control to their owner's hand rather than pay this spell's mana cost.
Draw two cards.

Shimmer of Possibility

Look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in a random order.

Riptide Survivor

Morph {1}{U}{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 this creature is turned face up, discard two cards, then draw three cards.

Watercourser

{U}: This creature gets +1/-1 until end of turn.

Tidespout Tyrant

Flying
Whenever you cast a spell, return target permanent to its owner's hand.

Tidal Force

At the beginning of each upkeep, you may tap or untap target permanent.

Tideforce Elemental

{U}, {T}: You may tap or untap another target creature.
Landfall — Whenever a land you control enters, you may untap this creature.

Hydromorph Guardian

{U}, Sacrifice this creature: Counter target spell that targets a creature you control.

Run Ashore

Choose one or both —
• The owner of target nonland permanent puts it on their choice of the top or bottom of their library.
• Return target nonland permanent to its owner's hand.

Subtlety

Flash
Flying
When this creature enters, choose up to one target creature spell or planeswalker spell. Its owner puts it on their choice of the top or bottom of their library.
Evoke—Exile a blue card from your hand.

Spectral Deluge

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.
Foretell {1}{U}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Downpour

Kaijin of the Vanishing Touch

Defender (This creature can't attack.)
Whenever this creature blocks a creature, return that creature to its owner's hand at end of combat. (Return it only if it's on the battlefield.)

Scuttletide

{1}, Discard a card: Create a 0/3 blue Crab creature token.
Delirium — Crabs you control get +1/+1 as long as there are four or more card types among cards in your graveyard.

Brine Elemental

Morph {5}{U}{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 this creature is turned face up, each opponent skips their next untap step.

Rivendell

Rivendell enters tapped unless you control a legendary creature.
{T}: Add {U}.
{1}{U}, {T}: Scry 2. Activate only if you control a legendary creature.

Waterkin Shaman

Whenever a creature you control with flying enters, this creature gets +1/+1 until end of turn.

Floodhound

{3}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Flood of Tears

Return all nonland permanents to their owners' hands. If you return four or more nontoken permanents you control this way, you may put a permanent card from your hand onto the battlefield.

Sea God's Revenge

Return up to three target creatures your opponents control to their owners' hands. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Slimy Aquarium

When you unlock this door, manifest dread, then put a +1/+1 counter on that creature.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Underwater Tunnel

When you unlock this door, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Underwater Tunnel // Slimy Aquarium

Island

Living Tsunami

Flying
At the beginning of your upkeep, sacrifice this creature unless you return a land you control to its owner's hand.