Prismatic Vista

{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Path of Ancestry

Path of Ancestry enters the battlefield 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.)

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Sword of War and Peace

Equipped creature gets +2/+2 and has protection from red and from white.
Whenever equipped creature deals combat damage to a player, Sword of War and Peace deals damage to that player equal to the number of cards in their hand and you gain 1 life for each card in your hand.
Equip {2}

Saprazzan Legate

If an opponent controls a Mountain and you control an Island, you may cast this spell without paying its mana cost.
Flying

Prevent all combat damage that would be dealt 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}.)

Sword of Hearth and Home

Equipped creature gets +2/+2 and has protection from green and from white.
Whenever equipped creature deals combat damage to a player, exile up to one target creature you own, then search your library for a basic land card. Put both cards onto the battlefield under your control, then shuffle.
Equip {2}

Nature's Lore

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

Forest

Prime Speaker Zegana

Prime Speaker Zegana enters the battlefield with X +1/+1 counters on it, where X is the greatest power among other creatures you control.
When Prime Speaker Zegana enters the battlefield, draw cards equal to its power.

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.)

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.

Lord of Atlantis

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

Subtlety

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

Rishadan Dockhand

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
{1}, {T}: Tap target land.

Sword of Light and Shadow

Equipped creature gets +2/+2 and has protection from white and from black.
Whenever equipped creature deals combat damage to a player, you gain 3 life and you may return up to one target creature card from your graveyard to your hand.
Equip {2}

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Ghost Town

{T}: Add {C}.
{0}: Return Ghost Town to its owner's hand. Activate only if it's not your turn.

Coral Atoll

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}.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Exploration

You may play an additional land on each of your turns.

Boomerang

Return target permanent to its owner's hand.

Dark Depths

Dark Depths enters the battlefield with ten ice counters on it.
{3}: Remove an ice counter from Dark Depths.
When Dark Depths has no ice counters on it, sacrifice it. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

Rootwater Thief

{U}: Rootwater Thief gains flying until end of turn.
Whenever Rootwater Thief deals combat damage to a player, you may pay {2}. If you do, search that player's library for a card and exile it, then the player shuffles.

Sylvan Scrying

Search your library for a land card, reveal it, put it into your hand, then shuffle.

Tidal Visionary

{T}: Target creature becomes the color of your choice until end of turn.

Pendelhaven

{T}: Add {G}.
{T}: Target 1/1 creature gets +1/+2 until end of turn.

Saprazzan Heir

Whenever Saprazzan Heir becomes blocked, you may draw three cards.

Field of Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Field of Ruin: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

Hurricane

Hurricane deals X damage to each creature with flying and each player.

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.")

Sword of Fire and Ice

Equipped creature gets +2/+2 and has protection from red and from blue.
Whenever equipped creature deals combat damage to a player, Sword of Fire and Ice deals 2 damage to any target and you draw a card.
Equip {2}

Hinterland Harbor

Hinterland Harbor enters the battlefield tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Unclaimed Territory

As Unclaimed Territory enters the battlefield, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

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.

Ensnare

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

Mystic Confluence

Choose three. You may choose the same mode more than once.
• Counter target spell unless its controller pays {3}.
• Return target creature to its owner's hand.
• Draw a card.

Voidslime

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Seahunter

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

Coastal Piracy

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

Archmage's Charm

Choose one —
• Counter target spell.
• Target player draws two cards.
• Gain control of target nonland permanent with mana value 1 or less.

Merfolk of the Pearl Trident

Sylvan Library

At the beginning of your draw step, you may draw two additional cards. If you do, choose two cards in your hand drawn this turn. For each of those cards, pay 4 life or put the card on top of your library.

Farseek

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

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.

Island

Maze of Ith

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

True-Name Nemesis

As True-Name Nemesis enters the battlefield, choose a player.
True-Name Nemesis has protection from the chosen player.

Crop Rotation

As an additional cost to cast this spell, sacrifice a land.
Search your library for a land card, put that card onto the battlefield, then shuffle.

Merfolk Looter

Thespian's Stage

{T}: Add {C}.
{2}, {T}: Thespian's Stage becomes a copy of target land, except it has this ability.

Flare of Denial

You may sacrifice a nontoken blue creature rather than pay this spell's mana cost.
Counter target spell.

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.

Tidal Courier

When Tidal Courier enters the battlefield, reveal the top four cards of your library. Put all Merfolk cards revealed this way into your hand and the rest on the bottom of your library in any order.
{3}{U}: Tidal Courier gains flying until end of turn.

Vodalian Merchant

When Vodalian Merchant enters the battlefield, draw a card, then discard a card.

Overrun

Creatures you control get +3/+3 and gain trample until end of turn.

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}.

Talisman of Curiosity

{T}: Add {C}.
{T}: Add {G} or {U}. Talisman of Curiosity deals 1 damage to you.

Rootwater Diver

{T}, Sacrifice Rootwater Diver: Return target artifact card from your graveyard to your hand.

Fellwar Stone

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

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Command Tower

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

Arcane Signet

Beast Within

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

Sword of Feast and Famine

Equipped creature gets +2/+2 and has protection from black and from green.
Whenever equipped creature deals combat damage to a player, that player discards a card and you untap all lands you control.
Equip {2}

Trade Routes

{1}: Return target land you control to its owner's hand.
{1}, Discard a land card: Draw a card.

Reef Shaman

{T}: Target land becomes the basic land type of your choice until end of turn.

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Gaea's Cradle

{T}: Add {G} for each creature you control.

Merfolk Assassin

{T}: Destroy target creature with islandwalk.

Rootwater Commando

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

Darting Merfolk

{U}: Return Darting Merfolk to its owner's hand.

Force of Will

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

Crucible of Worlds

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.

Empress Galina

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

Coral Merfolk

Guardian Project

Whenever a nontoken creature enters the battlefield under your control, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Rhystic Study

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

Breeding Pool

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

Counterspell

Reliquary Tower

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

Tatyova, Benthic Druid

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

Whirlpool Rider

When Whirlpool Rider enters the battlefield, shuffle the cards from your hand into your library, then draw that many cards.

Simic Signet

Gaea's Skyfolk

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.

Sol Ring

Ancestral Memories

Look at the top seven cards of your library. Put two of them into your hand and the rest into your graveyard.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Dress Down

Flash
When Dress Down enters the battlefield, draw a card.
Creatures lose all abilities.
At the beginning of the end step, sacrifice Dress Down.