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.

Prismatic Vista

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

Mask of Memory

Whenever equipped creature deals combat damage to a player, you may draw two cards. If you do, discard a card.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Archmage Ascension

At the beginning of each end step, if you drew two or more cards this turn, you may put a quest counter on Archmage Ascension.
As long as Archmage Ascension has six or more quest counters on it, if you would draw a card, you may instead search your library for a card, put that card into your hand, then shuffle.

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.

Master of Waves

Protection from red
Elemental creatures you control get +1/+1.
When Master of Waves enters, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Cloudpost

Cloudpost enters tapped.
{T}: Add {C} for each Locus on the battlefield.

Spellstutter Sprite

Flash
Flying
When Spellstutter Sprite enters, counter target spell with mana value X or less, where X is the number of Faeries you control.

Field of the Dead

Field of the Dead enters tapped.
{T}: Add {C}.
Whenever Field of the Dead or another land you control enters, if you control seven or more lands with different names, create a 2/2 black Zombie creature token.

Pyramid of the Pantheon

{2}, {T}: Add one mana of any color. Put a brick counter on Pyramid of the Pantheon.
{T}: Add three mana of any one color. Activate only if there are three or more brick counters on Pyramid of the Pantheon.

Merrow Commerce

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

Riverwise Augur

When Riverwise Augur enters, draw three cards, then put two cards from your hand on top of your library in any order.

Snow-Covered Swamp

Treasure Cove

(Transforms from Treasure Map.)
{T}: Add {C}.
{T}, Sacrifice a Treasure: Draw a card.

Treasure Map

{1}, {T}: Scry 1. Put a landmark counter on Treasure Map. Then if there are three or more landmark counters on it, remove those counters, transform Treasure Map, and create three Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Treasure Map // Treasure Cove

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.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Underground Sea

Ashiok, Dream Render

Spells and abilities your opponents control can't cause their controller to search their library.
−1: Target player mills four cards. Then exile each opponent's graveyard.

Disciple of the Ring

{1}, Exile an instant or sorcery card from your graveyard: Choose one —
• Counter target noncreature spell unless its controller pays {2}.
• Disciple of the Ring gets +1/+1 until end of turn.
• Tap target creature.
• Untap target creature.

Cursecatcher

Sacrifice Cursecatcher: Counter target instant or sorcery spell unless its controller pays {1}.

Necrotic Ooze

As long as Necrotic Ooze is on the battlefield, it has all activated abilities of all creature cards in all graveyards.

Snow-Covered Island

Sol Ring

Thassa, God of the Sea

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.

Memnarch

{1}{U}{U}: Target permanent becomes an artifact in addition to its other types. (This effect lasts indefinitely.)
{3}{U}: Gain control of target artifact. (This effect lasts indefinitely.)

Mistcaller

Sacrifice Mistcaller: Until end of turn, if a nontoken creature would enter and it wasn't cast, exile it instead.

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.")

Lonely Sandbar

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

Merfolk Mesmerist

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.

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.)

Cavern of Souls

As Cavern of Souls 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, and that spell can't be countered.

Vodalian Mage

{U}, {T}: Counter target spell unless its controller pays {1}.

Siren Stormtamer

Flying
{U}, Sacrifice Siren Stormtamer: Counter target spell or ability that targets you or a creature you control.

Patron Wizard

Tap an untapped Wizard you control: Counter target spell unless its controller pays {1}.

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Barrin, Tolarian Archmage

When Barrin, Tolarian Archmage enters, return up to one other target creature or planeswalker to its owner's hand.
At the beginning of your end step, if a permanent was put into your hand from the battlefield this turn, draw a card.

Myriad Landscape

Myriad Landscape enters 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.

Cephalid Coliseum

{T}: Add {U}. Cephalid Coliseum deals 1 damage to you.
Threshold — {U}, {T}, Sacrifice Cephalid Coliseum: Target player draws three cards, then discards three cards. Activate only if seven or more cards are in your graveyard.

Disruptive Student

{T}: Counter target spell unless its controller pays {1}.

Drowner of Secrets

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

Stonybrook Angler

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

Teferi, Mage of Zhalfir

Flash
Creature cards you own that aren't on the battlefield have flash.
Each opponent can cast spells only any time they could cast a sorcery.

Venser, Shaper Savant

Flash
When Venser, Shaper Savant enters, return target spell or permanent to its owner's hand.

Expedition Map

{2}, {T}, Sacrifice Expedition Map: Search your library for a land card, reveal it, put it into your hand, then shuffle.

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.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Arcanis the Omnipotent

{T}: Draw three cards.
{2}{U}{U}: Return Arcanis the Omnipotent to its owner's hand.

Swamp

Remote Isle

Remote Isle enters tapped.
{T}: Add {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Seafloor Oracle

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

Thassa's Oracle

When Thassa's Oracle enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Cryptic Caves

{T}: Add {C}.
{1}, {T}, Sacrifice Cryptic Caves: Draw a card. Activate only if you control five or more lands.

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.

Vodalian Illusionist

{U}{U}, {T}: Target creature phases out. (While it's phased out, it's treated as though it doesn't exist. It phases in before its controller untaps during their next untap step.)

Silumgar Sorcerer

Flash (You may cast this spell any time you could cast an instant.)
Flying
Exploit (When this creature enters, you may sacrifice a creature.)
When Silumgar Sorcerer exploits a creature, counter target creature spell.

Sigil Tracer

{1}{U}, Tap two untapped Wizards you control: Copy target instant or sorcery spell. You may choose new targets for the copy.

Herald's Horn

As Herald's Horn enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Teferi, Master of Time

You may activate loyalty abilities of Teferi, Master of Time on any player's turn any time you could cast an instant.
+1: Draw a card, then discard a card.
−3: Target creature you don't control phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)
−10: Take two extra turns after this one.

Razorfin Abolisher

{1}{U}, {T}: Return target creature with a counter on it to its owner's hand.

Sea Scryer

Sand Silos

Sand Silos enters tapped.
You may choose not to untap Sand Silos during your untap step.
At the beginning of your upkeep, if Sand Silos is tapped, put a storage counter on it.
{T}, Remove any number of storage counters from Sand Silos: Add {U} for each storage counter removed this way.

Sage of Fables

Each other Wizard creature you control enters with an additional +1/+1 counter on it.
{2}, Remove a +1/+1 counter from a creature you control: Draw a card.

Myojin of Seeing Winds

Myojin of Seeing Winds enters with a divinity counter on it if you cast it from your hand.
Myojin of Seeing Winds has indestructible as long as it has a divinity counter on it.
Remove a divinity counter from Myojin of Seeing Winds: Draw a card for each permanent you control.

Gyruda, Doom of Depths

Companion — Your starting deck contains only cards with even mana values. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
When Gyruda enters, each player mills four cards. Put a creature card with an even mana value from among the milled cards onto the battlefield under your control.

Azcanta, the Sunken Ruin

(Transforms from Search for Azcanta.)
{T}: Add {U}.
{2}{U}, {T}: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Search for Azcanta

At the beginning of your upkeep, surveil 1. Then if you have seven or more cards in your graveyard, you may transform Search for Azcanta. (Look at the top card of your library. You may put that card into your graveyard.)

Search for Azcanta // Azcanta, the Sunken Ruin

Prismwake Merrow

Flash
When Prismwake Merrow enters, target permanent becomes the color or colors of your choice until end of turn.

Saprazzan Cove

Saprazzan Cove enters tapped.
{T}: Put a storage counter on Saprazzan Cove.
{T}, Remove any number of storage counters from Saprazzan Cove: Add {U} for each storage counter removed this way.

Merfolk Trickster

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

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.

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters tapped unless you control two or more basic lands.

Terrarion

Terrarion enters tapped.
{2}, {T}, Sacrifice Terrarion: Add two mana in any combination of colors.
When Terrarion is put into a graveyard from the battlefield, draw a card.

Paradise Mantle

Equipped creature has "{T}: Add one mana of any color."
Equip {1}

Mystic Sanctuary

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

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.

Sage's Dousing

Counter target spell unless its controller pays {3}. If you control a Wizard, draw a card.

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.

Memory Plunder

You may cast target instant or sorcery card from an opponent's graveyard without paying its mana cost.

Glimmerpost

When Glimmerpost enters, you gain 1 life for each Locus on the battlefield.
{T}: Add {C}.

Tideshaper Mystic

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

Sea Gate Loremaster

{T}: Draw a card for each Ally you control.

Fallowsage

Whenever Fallowsage becomes tapped, you may draw a card.

Watery Grave

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

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.

Warden of Evos Isle

Flying
Creature spells with flying you cast cost {1} less to cast.

Towering-Wave Mystic

Whenever Towering-Wave Mystic deals damage, target player mills that many cards.

Merfolk Thaumaturgist

{T}: Switch target creature's power and toughness until end of turn.

Merrow Levitator

{T}: Target creature gains flying until end of turn.
Whenever you cast a blue spell, you may untap Merrow Levitator.

Cold Storage

{3}: Exile target creature you control.
Sacrifice Cold Storage: Return each creature card exiled with Cold Storage to the battlefield under your control.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Sage of the Falls

Whenever Sage of the Falls or another non-Human creature you control enters, you may draw a card. If you do, discard a card.

Island

Minamo, School at Water's Edge

{T}: Add {U}.
{U}, {T}: Untap target legendary permanent.

Merfolk Seer

When Merfolk Seer dies, you may pay {1}{U}. If you do, draw a card.

Simic Fluxmage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{1}{U}, {T}: Move a +1/+1 counter from Simic Fluxmage onto target creature.