Cathedral of War

Cathedral of War enters tapped.
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {C}.

Sygg, River Guide

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
{1}{W}: Target Merfolk you control gains protection from the color of your choice until end of turn.

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.

Shelldock Isle

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Shelldock Isle enters tapped.
{T}: Add {U}.
{U}, {T}: You may play the exiled card without paying its mana cost if a library has twenty or fewer cards in it.

Windbrisk Heights

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Windbrisk Heights enters tapped.
{T}: Add {W}.
{W}, {T}: You may play the exiled card without paying its mana cost if you attacked with three or more creatures this turn.

Return to Dust

Exile target artifact or enchantment. If you cast this spell during your main phase, you may exile up to one other target artifact or enchantment.

Paperfin Rascal

When Paperfin Rascal enters, clash with an opponent. If you win, put a +1/+1 counter on Paperfin Rascal. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Merrow Commerce

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

Kor Haven

{T}: Add {C}.
{1}{W}, {T}: Prevent all combat damage that would be dealt by target attacking creature this turn.

Tideshaper Mystic

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

Glacial Fortress

Glacial Fortress enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Divination

Wanderwine Prophets

Champion a Merfolk (When this enters, sacrifice it unless you exile another Merfolk you control. When this leaves the battlefield, that card returns to the battlefield.)
Whenever Wanderwine Prophets deals combat damage to a player, you may sacrifice a Merfolk. If you do, take an extra turn after this one.

Talrand, Sky Summoner

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

Jolting Merfolk

Fading 4 (This creature enters with four fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
Remove a fade counter from Jolting Merfolk: Tap target creature.

Militia's Pride

Whenever a nontoken creature you control attacks, you may pay {W}. If you do, create a 1/1 white Kithkin Soldier creature token that's tapped and attacking.

Forbidding Watchtower

Forbidding Watchtower enters tapped.
{T}: Add {W}.
{1}{W}: Forbidding Watchtower becomes a 1/5 white Soldier creature until end of turn. It's still a land.

Sivvi's Valor

If you control a Plains, you may tap an untapped creature you control rather than pay this spell's mana cost.
All damage that would be dealt to target creature this turn is dealt to you instead.

Belbe's Portal

As Belbe's Portal enters, choose a creature type.
{3}, {T}: You may put a creature card of the chosen type from your hand onto the battlefield.

Terrain Generator

{T}: Add {C}.
{2}, {T}: You may put a basic land card from your hand onto the battlefield tapped.

Austere Command

Choose two —
• Destroy all artifacts.
• Destroy all enchantments.
• Destroy all creatures with mana value 3 or less.
• Destroy all creatures with mana value 4 or greater.

Vivid Creek

Vivid Creek enters tapped with two charge counters on it.
{T}: Add {U}.
{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.

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.

Calciform Pools

{T}: Add {C}.
{1}, {T}: Put a storage counter on Calciform Pools.
{1}, Remove X storage counters from Calciform Pools: Add X mana in any combination of {W} and/or {U}.

Rootwater Commando

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

Bewilder

Target creature gets -3/-0 until end of turn.
Draw a card.

Evolving Wilds

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

Benthicore

When Benthicore enters, create two 1/1 blue Merfolk Wizard creature tokens.
Tap two untapped Merfolk you control: Untap Benthicore. It gains shroud until end of turn. (It can't be the target of spells or abilities.)

Blessed Reversal

You gain 3 life for each creature attacking you.

Crib Swap

Changeling (This card is every creature type.)
Exile target creature. Its controller creates a 1/1 colorless Shapeshifter creature token with changeling.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

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.

Plains

Drowner of Secrets

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

Crawlspace

No more than two creatures can attack you each combat.

Summon the School

Create two 1/1 blue Merfolk Wizard creature tokens.
Tap four untapped Merfolk you control: Return Summon the School from your graveyard to your hand.

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.

Silvergill Douser

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

Moonlace

Target spell or permanent becomes colorless.

Hoofprints of the Stag

Whenever you draw a card, you may put a hoofprint counter on Hoofprints of the Stag.
{2}{W}, Remove four hoofprint counters from Hoofprints of the Stag: Create a 4/4 white Elemental creature token with flying. Activate only during your turn.

Lotus Bloom

Suspend 3—{0} (Rather than cast this card from your hand, pay {0} and exile it with three 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.)
{T}, Sacrifice Lotus Bloom: Add three mana of any one color.

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.)

Talrand's Invocation

Create two 2/2 blue Drake creature tokens with flying.

Deeptread Merrow

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

Counter target spell. That spell's controller may draw a card.

Rewind

Counter target spell. Untap up to four lands.

Merrow Reejerey

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

Veteran of the Depths

Whenever Veteran of the Depths becomes tapped, you may put a +1/+1 counter on it.

Sivvi's Ruse

If an opponent controls a Mountain and you control a Plains, you may cast this spell without paying its mana cost.
Prevent all damage that would be dealt this turn to creatures 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.

Wings of Velis Vel

Changeling (This card is every creature type.)
Until end of turn, target creature has base power and toughness 4/4, gains all creature types, and gains flying.

Familiar's Ruse

As an additional cost to cast this spell, return a creature you control to its owner's hand.
Counter target spell.

Miscalculation

Counter target spell unless its controller pays {2}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Surgespanner

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

Momentary Blink

Exile target creature you control, then return it to the battlefield under its owner's control.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Shimmering Grotto

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

Wanderwine Hub

As Wanderwine Hub enters, you may reveal a Merfolk card from your hand. If you don't, Wanderwine Hub enters tapped.
{T}: Add {W} or {U}.

Knighthood

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.

Redirect

You may choose new targets for target spell.

Flagstones of Trokair

{T}: Add {W}.
When Flagstones of Trokair is put into a graveyard from the battlefield, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Reliquary Tower

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

Terramorphic Expanse

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

Levitation

Stonybrook Angler

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

Planar Cleansing

Fallowsage

Whenever Fallowsage becomes tapped, you may draw a card.

Unsummon

Return target creature to its owner's hand.

Rath's Edge

{T}: Add {C}.
{4}, {T}, Sacrifice a land: Rath's Edge deals 1 damage to any target.

Vivid Meadow

Vivid Meadow enters tapped with two charge counters on it.
{T}: Add {W}.
{T}, Remove a charge counter from Vivid Meadow: Add one mana of any color.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Mulldrifter

Flying
When Mulldrifter enters, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Inkfathom Divers

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
When Inkfathom Divers enters, look at the top four cards of your library, then put them back in any order.

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.

Spell Burst

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Counter target spell with mana value X.

Island

Darksteel Citadel

Faerie Conclave

Faerie Conclave enters tapped.
{T}: Add {U}.
{1}{U}: Faerie Conclave becomes a 2/1 blue Faerie creature with flying until end of turn. It's still a land.

Cryptic Command

Choose two —
• Counter target spell.
• Return target permanent to its owner's hand.
• Tap all creatures your opponents control.
• Draw a card.

Staff of Nin

At the beginning of your upkeep, draw a card.
{T}: Staff of Nin deals 1 damage to any target.

Scroll Thief

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

Ancestral Vision

Suspend 4—{U} (Rather than cast this card from your hand, pay {U} and exile it with four 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.)
Target player draws three cards.