Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Master of the Pearl Trident

Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Desert of the Mindful

Desert of the Mindful enters the battlefield tapped.
{T}: Add {U}.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)

Merfolk

Call to Mind

Return target instant or sorcery card from your graveyard to your hand.

High Tide

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

Ovinize

Until end of turn, target creature loses all abilities and has base power and toughness 0/1.

Lonely Sandbar

Lonely Sandbar enters the battlefield tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Harbinger of the Tides

You may cast Harbinger of the Tides as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
When Harbinger of the Tides enters the battlefield, you may return target tapped creature an opponent controls to its owner's hand.

Talrand, Sky Summoner

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

Curse of the Swine

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

Slinn Voda, the Rising Deep

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.

Castle Vantress

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

Whispering Wizard

Whenever you cast a noncreature spell, create a 1/1 white Spirit creature token with flying. This ability triggers only once each turn.

Cloud of Faeries

Flying
When Cloud of Faeries enters the battlefield, untap up to two lands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Island

Annul

Counter target artifact or enchantment spell.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Silundi Isle

Silundi Isle enters the battlefield tapped.
{T}: Add {U}.

Silundi Vision

Look at the top six 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 a random order.

Silundi Vision // Silundi Isle

Myriad Landscape

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.

Engulf the Shore

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

Ominous Sphinx

Flying
Whenever you cycle or discard a card, target creature an opponent controls gets -2/-0 until end of turn.

Trawler Drake

Flying
Trawler Drake enters the battlefield with an oil counter on it.
Trawler Drake gets +1/+1 for each oil counter on it.
Whenever you cast a noncreature spell, put an oil counter on Trawler Drake.

Veiled Serpent

When an opponent casts a spell, if Veiled Serpent is an enchantment, Veiled Serpent becomes a 4/4 Serpent creature with "This creature can't attack unless defending player controls an Island."
Cycling {2} ({2}, Discard this card: Draw a card.)

Boar

Ipnu Rivulet

{T}: Add {C}.
{T}, Pay 1 life: Add {U}.
{1}{U}, {T}, Sacrifice a Desert: Target player mills four cards.

Imprisoned in the Moon

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

Mind Spring

The Surgical Bay

The Surgical Bay enters the battlefield tapped.
{T}: Add {U}.
{1}{U}, {T}, Sacrifice The Surgical Bay: Draw a card.

Sol Ring

Bubble Snare

Kicker {2}{U} (You may pay an additional {2}{U} as you cast this spell.)
Enchant creature
When Bubble Snare enters the battlefield, if it was kicked, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Kefnet's Monument

Blue creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, target creature an opponent controls doesn't untap during its controller's next untap step.

Mystic Sanctuary

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

Thirst for Discovery

Draw three cards. Then discard two cards unless you discard a basic land card.

Ruin Crab

Landfall — Whenever a land enters the battlefield under your control, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Mist-Cloaked Herald

Flow of Ideas

Temple of the False God

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

Scourge of Fleets

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.

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

All-Seeing Arbiter

Flying
Whenever All-Seeing Arbiter enters the battlefield or attacks, draw two cards, then discard a card.
Whenever you discard a card, target creature an opponent controls gets -X/-0 until your next turn, where X is the number of different mana values among cards in your graveyard.

Merfolk Pupil

When Merfolk Pupil enters the battlefield, draw a card, then discard a card.
{1}{U}, Exile Merfolk Pupil from your graveyard: Draw a card, then discard a card.

Thassa's Rebuff

Counter target spell unless its controller pays {X}, where X is your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Crashing Tide

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

Turn Aside

Counter target spell that targets a permanent you control.

Tide Shaper

Kicker {1} (You may pay an additional {1} as you cast this spell.)
When Tide Shaper enters the battlefield, if it was kicked, target land becomes an Island for as long as Tide Shaper remains on the battlefield.
Tide Shaper gets +1/+1 as long as an opponent controls an Island.

Halimar Depths

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}.

Deeproot Waters

Whenever you cast a Merfolk spell, create a 1/1 blue Merfolk creature token with hexproof. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Wonder

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

Emperor Mihail II

You may look at the top card of your library any time.
You may cast Merfolk spells from the top of your library.
Whenever you cast a Merfolk spell, you may pay {1}. If you do, create a 1/1 blue Merfolk creature token.

Tazeem Roilmage

Kicker {4} (You may pay an additional {4} as you cast this spell.)
When Tazeem Roilmage enters the battlefield, if it was kicked, return target instant or sorcery card from your graveyard to your hand.

Stonybrook Banneret

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Merfolk spells and Wizard spells you cast cost {1} less to cast.

Open into Wonder

X target creatures can't be blocked this turn. Until end of turn, those creatures gain "Whenever this creature deals combat damage to a player, 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.

Jace, the Living Guildpact

+1: Look at the top two cards of your library. Put one of them into your graveyard.
−3: Return another target nonland permanent to its owner's hand.
−8: Each player shuffles their hand and graveyard into their library. You draw seven cards.

Mantle of Tides

Equipped creature gets +1/+2.
Whenever you draw your second card each turn, attach Mantle of Tides to target creature you control.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Flow of Knowledge

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

Bident of Thassa

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.

Sleep

Tap all creatures target player controls. Those creatures don't untap during that player's next untap step.

Finale of Revelation

Draw X cards. If X is 10 or more, instead shuffle your graveyard into your library, draw X cards, untap up to five lands, and you have no maximum hand size for the rest of the game.
Exile Finale of Revelation.

Saw It Coming

Counter target spell.
Foretell {1}{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.)

Familiar's Ruse

As an additional cost to cast this spell, return a creature you control to its owner's hand.
Counter target spell.

Quicksilver Fountain

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.

Spirit

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Drake

Seafloor Oracle

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

Omnispell Adept

{2}{U}, {T}: You may cast an instant or sorcery spell from your hand without paying its mana cost.

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

Dispel

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Mnemonic Wall

Defender
When Mnemonic Wall enters the battlefield, you may return target instant or sorcery card from your graveyard to your hand.

Brineborn Cutthroat

Flash (You may cast this spell any time you could cast an instant.)
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Brineborn Cutthroat.

Clear the Mind

Target player shuffles their graveyard into their library.
Draw a card.

Merfolk Sovereign

Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.

Svyelun of Sea and Sky

Svyelun of Sea and Sky has indestructible as long as you control at least two other Merfolk.
Whenever Svyelun attacks, draw a card.
Other Merfolk you control have ward {1}. (Whenever another Merfolk you control becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Cascade Seer

When Cascade Seer enters the battlefield, scry X, where X is the number of creatures in your party. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)

Lord of Atlantis

Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Seafloor Stalker

{4}{U}: Seafloor Stalker gets +1/+0 until end of turn and can't be blocked this turn. This ability costs {1} less to activate for each creature in your party. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)

Wash Out

Return all permanents of the color of your choice to their owners' hands.

Watchful Blisterzoa

Flying
Watchful Blisterzoa enters the battlefield with an oil counter on it.
When Watchful Blisterzoa dies, draw cards equal to the number of oil counters on it.

Fear of Death

Enchant creature
When Fear of Death enters the battlefield, mill two cards. (Put the top two cards of your library into your graveyard.)
Enchanted creature gets -X/-0, where X is the number of cards in your graveyard.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

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.