Fervent Denial

Counter target spell.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

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.

Scour All Possibilities

Scry 2, then draw a card.
Flashback {4}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Catalyst Stone

Flashback costs you pay cost {2} less.
Flashback costs your opponents pay cost {2} more.

Magus of the Jar

{T}, Sacrifice Magus of the Jar: Each player exiles all cards from their hand face down and draws seven cards. At the beginning of the next end step, each player discards their hand and returns to their hand each card they exiled this way.

Beguiler of Wills

{T}: Gain control of target creature with power less than or equal to the number of creatures you control.

Raving Visionary

{U}, {T}: Draw a card, then discard a card.
Delirium — {2}{U}, {T}: Draw a card. Activate only if there are four or more card types among cards in your graveyard.

Think Twice

Draw a card.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Glimpse of Freedom

Draw a card.
Escape—{2}{U}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Tidal Visionary

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

Drowner of Secrets

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

Trinket Mage

When Trinket Mage enters, you may search your library for an artifact card with mana value 1 or less, reveal that card, put it into your hand, then shuffle.

Rootwater Hunter

{T}: Rootwater Hunter deals 1 damage to any target.

Emry, Lurker of the Loch

This spell costs {1} less to cast for each artifact you control.
When Emry, Lurker of the Loch enters, mill four cards.
{T}: Choose target artifact card in your graveyard. You may cast that card this turn. (You still pay its costs. Timing rules still apply.)

Cackling Counterpart

Create a token that's a copy of target creature you control.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Have

Paradise Mantle

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

Slickshot Lockpicker

When Slickshot Lockpicker enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)
Plot {2}{U} (You may pay {2}{U} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Sea Scryer

Merfolk Mesmerist

Merrow Commerce

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

Otherworldly Gaze

Surveil 3. (Look at the top three cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Island

Inspiration from Beyond

Mill three cards, then return an instant or sorcery card from your graveyard to your hand.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Kelpie Guide

{T}: Untap another target permanent you control.
{T}: Tap target permanent. Activate only if you control eight or more lands.

Relic of Legends

{T}: Add one mana of any color.
Tap an untapped legendary creature you control: Add one mana of any color.

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.)

Grimoire Thief

Whenever Grimoire Thief becomes tapped, exile the top three cards of target opponent's library face down.
You may look at cards exiled with Grimoire Thief.
{U}, Sacrifice Grimoire Thief: Turn all cards exiled with Grimoire Thief face up. Counter all spells with those names.

Magus of the Bazaar

{T}: Draw two cards, then discard three cards.

Merrow Levitator

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

Stonybrook Angler

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

Merfolk Looter

Enclave Cryptologist

Level up {1}{U} ({1}{U}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
0/1
{T}: Draw a card, then discard a card.
LEVEL 3+
0/1
{T}: Draw a card.

Jace, Telepath Unbound

+1: Up to one target creature gets -2/-0 until your next turn.
−3: You may cast target instant or sorcery card from your graveyard this turn. If that spell would be put into your graveyard, exile it instead.
−9: You get an emblem with "Whenever you cast a spell, target opponent mills five cards."

Jace, Vryn's Prodigy

{T}: Draw a card, then discard a card. If there are five or more cards in your graveyard, exile Jace, Vryn's Prodigy, then return him to the battlefield transformed under his owner's control.

Jace, Vryn's Prodigy // Jace, Telepath Unbound

Merfolk Pupil

When Merfolk Pupil enters, draw a card, then discard a card.
{1}{U}, Exile Merfolk Pupil from your graveyard: Draw a card, then discard a card.

Razorfin Abolisher

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

Radical Idea

Draw a card.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Dakra Mystic

{U}, {T}: Each player reveals the top card of their library. You may put the revealed cards into their owners' graveyards. If you don't, each player draws a card.

Rootwater Diver

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

Defy Gravity

Target creature gains flying until end of turn.
Flashback {U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Vodalian Arcanist

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

Tidal Warrior

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

Merfolk Thaumaturgist

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

Surgespanner

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

Empress Galina

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

Moonsnare Prototype

{T}, Tap an untapped artifact or creature you control: Add {C}.
Channel — {4}{U}, Discard Moonsnare Prototype: The owner of target nonland permanent puts it on their choice of the top or bottom of their library.

Banishing Knack

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

Tideshaper Mystic

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

Self-Reflection

Create a token that's a copy of target creature you control.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Vodalian Mage

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

Quiet Speculation

Search target player's library for up to three cards with flashback and put them into that player's graveyard. Then the player shuffles.

Deeproot Pilgrimage

Whenever one or more nontoken Merfolk you control become tapped, create a 1/1 blue Merfolk creature token with hexproof.

Silvergill Douser

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

Neerdiv, Devious Diver

Whenever Neerdiv, Devious Diver becomes tapped, target player mills cards equal to its power.
Whenever you cast a spell from your graveyard or activate an ability of a card in your graveyard, draw a card and put a +1/+1 counter on Neerdiv.

Volshe Tideturner

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

Memory Deluge

Look at the top X cards of your library, where X is the amount of mana spent to cast this spell. Put two of them into your hand and the rest on the bottom of your library in a random order.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Reef Shaman

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

Goldberry, River-Daughter

{T}: Move a counter of each kind not on Goldberry, River-Daughter from another target permanent you control onto Goldberry.
{U}, {T}: Move one or more counters from Goldberry onto another target permanent you control. If you do, draw a card.

Fatestitcher

{T}: You may tap or untap another target permanent.
Unearth {U} ({U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Fallowsage

Whenever Fallowsage becomes tapped, you may draw a card.

Forensic Researcher

{T}: Untap another target permanent you control.
{T}, Collect evidence 3: Tap target creature you don't control. (To collect evidence 3, exile cards with total mana value 3 or greater from your graveyard.)

Maximize Altitude

Target creature gets +1/+1 and gains flying until end of turn.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this 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.

Fishing Pole

Equipped creature has "{1}, {T}, Tap Fishing Pole: Put a bait counter on Fishing Pole."
Whenever equipped creature becomes untapped, remove a bait counter from this Equipment. If you do, create a 1/1 blue Fish creature token.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Ioreth of the Healing House

{T}: Untap another target permanent.
{T}: Untap two other target legendary creatures.

Merfolk Sovereign

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

Artful Dodge

Target creature can't be blocked this turn.
Flashback {U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Soothsayer Adept

{1}{U}, {T}: Draw a card, then discard a card.

Rishadan Dockhand

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

Mist Dancer

Flying
Other Merfolk you control get +1/+0 and have flying.
Encore {5}{U}{U} ({5}{U}{U}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Chemister's Insight

Draw two cards.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)