Vodalian Wave-Knight

Whenever you draw a card, put a +1/+1 counter on each other Merfolk and/or Knight you control.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Seafloor Oracle

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

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Thrasios, Triton Hero

{4}: Scry 1, then reveal the top card of your library. If it's a land card, put it onto the battlefield tapped. Otherwise, draw a card.
Partner (You can have two commanders if both have partner.)

Lullmage Mentor

Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.
Tap seven untapped Merfolk you control: Counter target spell.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Thada Adel, Acquisitor

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.

Coat of Arms

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

Kindred Discovery

As Kindred Discovery enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Merfolk Mistbinder

Vodalian Hexcatcher

Flash
Other Merfolk you control get +1/+1.
Sacrifice a Merfolk: Counter target noncreature spell unless its controller pays {1}.

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Overgrown Tomb

({T}: Add {B} or {G}.)
As Overgrown Tomb enters, you may pay 2 life. If you don't, it enters tapped.

Sygg, River Cutthroat

At the beginning of each end step, if an opponent lost 3 or more life this turn, you may draw a card. (Damage causes loss of life.)

Merrow Harbinger

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
When Merrow Harbinger enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.

Cryptolith Rite

Creatures you control have "{T}: Add one mana of any color."

Godless Shrine

({T}: Add {W} or {B}.)
As Godless Shrine enters, you may pay 2 life. If you don't, it enters tapped.

Island

Scalding Tarn

{T}, Pay 1 life, Sacrifice Scalding Tarn: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Merrow Reejerey

Other Merfolk creatures you control get +1/+1.
Whenever you cast a Merfolk spell, you may tap or untap target permanent.

Lord of Atlantis

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

Misty Rainforest

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

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.

Command Tower

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

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Counterspell

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Plains

Summon the School

Create two 1/1 blue Merfolk Wizard creature tokens.
Tap four untapped Merfolk you control: Return Summon the School from your graveyard to your hand.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Temple Garden

({T}: Add {G} or {W}.)
As Temple Garden enters, you may pay 2 life. If you don't, it enters tapped.

Kumena, Tyrant of Orazca

Tap another untapped Merfolk you control: Kumena, Tyrant of Orazca can't be blocked this turn.
Tap three untapped Merfolk you control: Draw a card.
Tap five untapped Merfolk you control: Put a +1/+1 counter on each Merfolk you control.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Flooded Strand

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Spara's Headquarters

({T}: Add {G}, {W}, or {U}.)
Spara's Headquarters enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Tishana, Voice of Thunder

Tishana, Voice of Thunder's power and toughness are each equal to the number of cards in your hand.
You have no maximum hand size.
When Tishana enters, draw a card for each creature you control.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Breeding Pool

({T}: Add {G} or {U}.)
As Breeding Pool enters, you may pay 2 life. If you don't, it enters tapped.

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Windswept Heath

{T}, Pay 1 life, Sacrifice Windswept Heath: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

Forerunner of the Heralds

When Forerunner of the Heralds enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.
Whenever another Merfolk you control enters, put a +1/+1 counter on Forerunner of the Heralds.

Raffine's Tower

({T}: Add {W}, {U}, or {B}.)
Raffine's Tower enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Mystic Remora

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}.

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Cyclonic Rift

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.")

Marsh Flats

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Realmwalker

Changeling (This card is every creature type.)
As Realmwalker enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

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}.)

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

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.

Deeproot Elite

Whenever another Merfolk you control enters, put a +1/+1 counter on target Merfolk you control.

Skyshroud Claim

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

Merfolk Sovereign

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

Forest

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.)

Mana Confluence

{T}, Pay 1 life: Add one mana of any color.

Wanderwine Hub

As Wanderwine Hub enters, you may reveal a Merfolk card from your hand. If you don't, Wanderwine Hub enters tapped.
{T}: Add {W} or {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.)

Tatyova, Benthic Druid

Landfall — Whenever a land you control enters, you gain 1 life and draw a card.

Surgespanner

Whenever Surgespanner becomes tapped, you may pay {1}{U}. If you do, return target permanent to its owner's hand.

Deeproot Wayfinder

Whenever Deeproot Wayfinder deals combat damage to a player or battle, surveil 1, then you may return a land card from your graveyard to the battlefield tapped. (To surveil 1, look at the top card of your library. You may put that card into your graveyard.)

Arcane Signet

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters, you may pay 2 life. If you don't, it enters tapped.

Judge of Currents

Whenever a Merfolk you control becomes tapped, you may gain 1 life.

Kiora's Follower

Indatha Triome

({T}: Add {W}, {B}, or {G}.)
Indatha Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Kopala, Warden of Waves

Spells your opponents cast that target a Merfolk you control cost {2} more to cast.
Abilities your opponents activate that target a Merfolk you control cost {2} more to activate.

Tide Shaper

Kicker {1} (You may pay an additional {1} as you cast this spell.)
When Tide Shaper enters, 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.

Tymna the Weaver

Lifelink
At the beginning of each of your postcombat main phases, you may pay X life, where X is the number of opponents that were dealt combat damage this turn. If you do, draw X cards.
Partner (You can have two commanders if both have partner.)

Stonybrook Schoolmaster

Whenever Stonybrook Schoolmaster becomes tapped, you may create a 1/1 blue Merfolk Wizard creature token.

Cold-Eyed Selkie

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Cold-Eyed Selkie deals combat damage to a player, you may draw that many cards.

Merrow Commerce

At the beginning of your end step, untap all Merfolk you control.

Thieving Skydiver

Kicker {X}. X can't be 0. (You may pay an additional {X} as you cast this spell.)
Flying
When Thieving Skydiver enters, if it was kicked, gain control of target artifact with mana value X or less. If that artifact is an Equipment, attach it to Thieving Skydiver.

Wanderwine Prophets

Champion a Merfolk (When this enters, sacrifice it unless you exile another Merfolk you control. When this leaves the battlefield, that card returns to the battlefield.)
Whenever Wanderwine Prophets deals combat damage to a player, you may sacrifice a Merfolk. If you do, take an extra turn after this one.

Sol Ring

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.

Rejuvenating Springs

Rejuvenating Springs enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Sygg, River Guide

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
{1}{W}: Target Merfolk you control gains protection from the color of your choice until end of turn.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Seahunter

{3}, {T}: Search your library for a Merfolk permanent card, put it onto the battlefield, then shuffle.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Verdant Catacombs

{T}, Pay 1 life, Sacrifice Verdant Catacombs: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

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.

Inkfathom Witch

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{2}{U}{B}: Each unblocked creature has base power and toughness 4/1 until end of turn.

Reflections of Littjara

As Reflections of Littjara enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Aquitect's Will

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.