Evolving Wilds

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

Tempest Caller

When Tempest Caller enters the battlefield, tap all creatures target opponent controls.

World Shaper

Whenever World Shaper attacks, you may mill three cards.
When World Shaper dies, return all land cards from your graveyard to the battlefield tapped.

Storm Sculptor

Storm Sculptor can't be blocked.
When Storm Sculptor enters the battlefield, return a creature you control to its owner's hand.

Treasure Hunt

Reveal cards from the top of your library until you reveal a nonland card, then put all cards revealed this way into your hand.

Cosi's Trickster

Whenever an opponent shuffles their library, you may put a +1/+1 counter on Cosi's Trickster.

Jade Bearer

When Jade Bearer enters the battlefield, put a +1/+1 counter on another target Merfolk you control.

Search for Tomorrow

Search your library for a basic land card, put it onto the battlefield, then shuffle.
Suspend 2—{G} (Rather than cast this card from your hand, you may pay {G} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Waterknot

Enchant creature
When Waterknot enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

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 the battlefield, draw a card for each creature you control.

High Tide

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

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

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.

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.

Storm Cauldron

Each player may play an additional land during each of their turns.
Whenever a land is tapped for mana, return it to its owner's hand.

Nature's Will

Whenever one or more creatures you control deal combat damage to a player, tap all lands that player controls and untap all lands you control.

Mana Breach

Whenever a player casts a spell, that player returns a land they control to its owner's hand.

Scroll Thief

Whenever Scroll Thief deals combat damage to a player, draw a card.

Lonely Sandbar

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

Run Aground

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

Botanical Sanctum

Botanical Sanctum enters the battlefield tapped unless you control two or fewer other lands.
{T}: Add {G} or {U}.

Merfolk Trickster

Flash
When Merfolk Trickster enters the battlefield, tap target creature an opponent controls. It loses all abilities until end of turn.

Clear the Mind

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

Retreat to Coralhelm

Landfall — Whenever a land enters the battlefield under your control, choose one —
• You may tap or untap target creature.
• Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Aquatic Incursion

When Aquatic Incursion enters the battlefield, create two 1/1 blue Merfolk creature tokens with hexproof. (They can't be the targets of spells or abilities your opponents control.)
{3}{U}: Target Merfolk can't be blocked this turn.

Unknown Shores

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

Coastal Breach

Undaunted (This spell costs {1} less to cast for each opponent.)
Return all nonland permanents to their owners' hands.

Tidal Warrior

{T}: Target land becomes an Island until end of turn.

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.

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.

Terramorphic Expanse

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

Vineshaper Mystic

When Vineshaper Mystic enters the battlefield, put a +1/+1 counter on each of up to two target Merfolk you control.

Kiora, the Crashing Wave

+1: Until your next turn, prevent all damage that would be dealt to and dealt by target permanent an opponent controls.
−1: Draw a card. You may play an additional land this turn.
−5: You get an emblem with "At the beginning of your end step, create a 9/9 blue Kraken creature token."

Migration Path

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.
Cycling {2} ({2}, Discard this card: Draw a card.)

Crashing Tide

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

Rampant Growth

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

Thornwood Falls

Thornwood Falls enters the battlefield tapped.
When Thornwood Falls enters the battlefield, you gain 1 life.
{T}: Add {G} or {U}.

Grip of the Roil

Surge {1}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Tap target creature. It doesn't untap during its controller's next untap step.
Draw a card.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Reef Shaman

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

Naturalize

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.)

Reliquary Tower

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

Blackblade Reforged

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

Gush

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

Explore

You may play an additional land this turn.
Draw a card.

Explosive Vegetation

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

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Manabond

At the beginning of your end step, you may reveal your hand and put all land cards from it onto the battlefield. If you do, discard your hand.

Lord of Atlantis

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

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.

Streambed Aquitects

{T}: Target Merfolk creature gets +1/+1 and gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.)
{T}: Target land becomes an Island until end of turn.

Tatyova, Benthic Druid

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

Woodland Stream

Woodland Stream enters the battlefield tapped.
{T}: Add {G} or {U}.

Lumbering Falls

Lumbering Falls enters the battlefield tapped.
{T}: Add {G} or {U}.
{2}{G}{U}: Lumbering Falls becomes a 3/3 green and blue Elemental creature with hexproof until end of turn. It's still a land.

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.

Khalni Gem

When Khalni Gem enters the battlefield, return two lands you control to their owner's hand.
{T}: Add two mana of any one color.

Forest

Warped Landscape

{T}: Add {C}.
{2}, {T}, Sacrifice Warped Landscape: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Excavation

{1}, Sacrifice a land: Draw a card. Any player may activate this ability.

Summer Bloom

You may play up to three additional lands this turn.

Jungleborn Pioneer

When Jungleborn Pioneer enters the battlefield, create a 1/1 blue Merfolk creature token with hexproof. (It can't be the target of spells or abilities your opponents control.)

Vodalian Arcanist

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.

Moonring Island

({T}: Add {U}.)
Moonring Island enters the battlefield tapped.
{U}, {T}: Look at the top card of target player's library. Activate only if you control two or more blue permanents.

Silvergill Adept

As an additional cost to cast this spell, reveal a Merfolk card from your hand or pay {3}.
When Silvergill Adept enters the battlefield, draw a card.

Horn of Greed

Whenever a player plays a land, that player draws a card.

Island

Urban Evolution

Draw three cards. You may play an additional land this turn.

Enter the Unknown

Target creature you control explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.)
You may play an additional land this turn.

Avenger of Zendikar

When Avenger of Zendikar enters the battlefield, create a 0/1 green Plant creature token for each land you control.
Landfall — Whenever a land enters the battlefield under your control, you may put a +1/+1 counter on each Plant creature you control.

Path of Discovery

Whenever a creature enters the battlefield under your control, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.)

Temple of Mystery

Temple of Mystery enters the battlefield tapped.
When Temple of Mystery enters the battlefield, scry 1.
{T}: Add {G} or {U}.

Simic Growth Chamber

Simic Growth Chamber enters the battlefield tapped.
When Simic Growth Chamber enters the battlefield, return a land you control to its owner's hand.
{T}: Add {G}{U}.

Tishana's Wayfinder

When Tishana's Wayfinder enters the battlefield, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Merfolk Sovereign

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