Silvergill Douser

{T}: Target creature gets -X/-0 until end of turn, where X is the number of Merfolk and/or Faeries you control.

Coral Trickster

Morph {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 Coral Trickster is turned face up, you may tap or untap target permanent.

Terramorphic Expanse

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

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.)

Trait Doctoring

Change the text of target permanent by replacing all instances of one color word with another or one basic land type with another until end of turn.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Chief Engineer

Artifact spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting an artifact spell pays for {1} or one mana of that creature's color.)

Scroll Thief

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

Exotic Orchard

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

Sol Ring

Nature's Lore

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

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.

Seafloor Oracle

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

Tideshaper Mystic

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

Circular Logic

Counter target spell unless its controller pays {1} for each card in your graveyard.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Ovinize

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

Talrand, Sky Summoner

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

Tempest Caller

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

Deeproot Champion

Whenever you cast a noncreature spell, put a +1/+1 counter on Deeproot Champion.

Clone

You may have Clone enter as a copy of any creature on the battlefield.

Chart a Course

Draw two cards. Then discard a card unless you attacked this turn.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Drowner of Secrets

Tap an untapped Merfolk you control: Target player mills a card.

Ertai's Scorn

This spell costs {U} less to cast if an opponent cast two or more spells this turn.
Counter target spell.

Precognitive Perception

Draw three cards.
Addendum — If you cast this spell during your main phase, instead scry 3, then draw three cards.

Tatyova, Benthic Druid

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

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Silvergill Adept

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

Secluded Courtyard

As Secluded Courtyard enters, 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 or activate an ability of a creature source of the chosen type.

Merfolk Trickster

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

Birds of Paradise

High Tide

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

Tatyova, Steward of Tides

Land creatures you control have flying.
Whenever a land you control enters, if you control seven or more lands, up to one target land you control becomes a 3/3 Elemental creature with haste. It's still a land.

Merfolk Skydiver

Flying
When Merfolk Skydiver enters, put a +1/+1 counter on target creature you control.
{3}{G}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Murkfiend Liege

Other green creatures you control get +1/+1.
Other blue creatures you control get +1/+1.
Untap all green and/or blue creatures you control during each other player's untap step.

Seahunter

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

Arbor Elf

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.

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.

Tangled Islet

({T}: Add {G} or {U}.)
Tangled Islet enters tapped.

Augur of Bolas

When Augur of Bolas enters, look at the top three 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 any order.

Fallowsage

Whenever Fallowsage becomes tapped, you may draw a card.

Voda Sea Scavenger

Domain — When Voda Sea Scavenger enters, look at the top X cards of your library, where X is the number of basic land types among lands you control. You may put one of those cards on top of your library. Put the rest on the bottom of your library in a random order.

Obsessive Search

Draw a card.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Simic Growth Chamber

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

Jungle Delver

{3}{G}: Put a +1/+1 counter on Jungle Delver.

Deeproot Warrior

Whenever Deeproot Warrior becomes blocked, it gets +1/+1 until end of turn.

Bounty of the Luxa

At the beginning of your first main phase, remove all flood counters from Bounty of the Luxa. If no counters were removed this way, put a flood counter on Bounty of the Luxa and draw a card. Otherwise, add {C}{G}{U}.

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.

Unsummon

Return target creature to its owner's hand.

Herald of Secret Streams

Creatures you control with +1/+1 counters on them can't be blocked.

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.

Llanowar Elves

Unnatural Restoration

Return target permanent card from your graveyard to your hand. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Vodalian Hexcatcher

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

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.)

Vineshaper Mystic

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

Tamiyo, Compleated Sage

Compleated ({G/U/P} can be paid with {G}, {U}, or 2 life. If life was paid, this planeswalker enters with two fewer loyalty counters.)
+1: Tap up to one target artifact or creature. It doesn't untap during its controller's next untap step.
−X: Exile target nonland permanent card with mana value X from your graveyard. Create a token that's a copy of that card.
−7: Create Tamiyo's Notebook, a legendary colorless artifact token with "Spells you cast cost {2} less to cast" and "{T}: Draw a card."

Merfolk Sovereign

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

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, you may return target tapped creature an opponent controls to its owner's hand.

Naturalize

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.

Essence Scatter

Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Mystical Tutor

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

Yavimaya Coast

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

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.

Impulse

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 any order.

Negate

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Reject Imperfection

Counter target spell. If that spell's mana value was 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Stonybrook Angler

{1}{U}, {T}: You may tap or untap target creature.

Essence Capture

Counter target creature spell. Put a +1/+1 counter on up to one target creature you control.

Experimental Augury

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

The Surgical Bay

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

Volshe Tideturner

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

Invigorating Surge

Put a +1/+1 counter on target creature you control, then double the number of +1/+1 counters on that creature.

Riptide Pilferer

Whenever Riptide Pilferer deals combat damage to a player, that player discards a card.
Morph {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.)

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.

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Tazeem Roilmage

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

Thornwood Falls

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

Deeptread Merrow

{U}: Deeptread Merrow gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.)

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.")

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.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

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.

Merrow Reejerey

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

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.

Merrow Commerce

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

Snap

Return target creature to its owner's hand. Untap up to two lands.

Coral Merfolk

Benthic Biomancer

{1}{U}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Benthic Biomancer, draw a card, then discard a card.

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.

Kiora, Behemoth Beckoner

Whenever a creature you control with power 4 or greater enters, draw a card.
−1: Untap target permanent.

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}.)

Deeproot Elite

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

Mist-Cloaked Herald

Emergent Growth

Target creature gets +5/+5 until end of turn and must be blocked this turn if able.

Wood Elves

When Wood Elves enters, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Counterspell

Headwater Sentries

Back to Nature

Reclamation Sage

When Reclamation Sage enters, you may destroy target artifact or enchantment.

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.