Merfolk Assassin

{T}: Destroy target creature with islandwalk.

Island

Rootwater Diver

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

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.)

Thing from the Deep

Whenever Thing from the Deep attacks, sacrifice it unless you sacrifice an Island.

Seasinger

When you control no Islands, sacrifice Seasinger.
You may choose not to untap Seasinger during your untap step.
{T}: Gain control of target creature whose controller controls an Island for as long as you control Seasinger and Seasinger remains tapped.

Counterspell

Faces of the Past

Whenever a creature dies, tap all untapped creatures that share a creature type with it or untap all tapped creatures that share a creature type with it.

Treasure Cruise

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Draw three cards.

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.

War Barge

{3}: Target creature gains islandwalk until end of turn. When War Barge leaves the battlefield this turn, destroy that creature. A creature destroyed this way can't be regenerated. (A creature with islandwalk can't be blocked as long as defending player controls an Island.)

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.)

Tangle Kelp

Enchant creature
When Tangle Kelp enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step if it attacked during its controller's last turn.

Denizen of the Deep

When Denizen of the Deep enters, return each other creature you control to its owner's hand.

Tidal Warrior

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

Lord of Atlantis

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

Vodalian War Machine

Defender (This creature can't attack.)
Tap an untapped Merfolk you control: Vodalian War Machine can attack this turn as though it didn't have defender.
Tap an untapped Merfolk you control: Vodalian War Machine gets +2/+1 until end of turn.
When Vodalian War Machine dies, destroy all Merfolk tapped this turn to pay for its abilities.

Benthic Explorers

{T}, Untap a tapped land an opponent controls: Add one mana of any type that land could produce.

Magical Hack

Change the text of target spell or permanent by replacing all instances of one basic land type with another. (For example, you may change "swampwalk" to "plainswalk." This effect lasts indefinitely.)

Arch of Orazca

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
{T}: Add {C}.
{5}, {T}: Draw a card. Activate only if you have the city's blessing.

River Merfolk

{U}: River Merfolk gains mountainwalk until end of turn. (It can't be blocked as long as defending player controls a Mountain.)

Svyelunite Temple

Svyelunite Temple enters tapped.
{T}: Add {U}.
{T}, Sacrifice Svyelunite Temple: Add {U}{U}.

Saprazzan Heir

Whenever Saprazzan Heir becomes blocked, you may draw three cards.

Mana Vapors

Lands target player controls don't untap during their next untap step.

Marjhan

Marjhan doesn't untap during your untap step.
{U}{U}, Sacrifice a creature: Untap Marjhan. Activate only during your upkeep.
Marjhan can't attack unless defending player controls an Island.
{U}{U}: Marjhan gets -1/-0 until end of turn and deals 1 damage to target attacking creature without flying.
When you control no Islands, sacrifice Marjhan.

Disdainful Stroke

Counter target spell with mana value 4 or greater.

Tidal Visionary

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

Merfolk of the Pearl Trident

Rootwater Mystic

{1}{U}: Look at the top card of target player's library.

Volcanic Eruption

Destroy X target Mountains. Volcanic Eruption deals damage to each creature and each player equal to the number of Mountains put into a graveyard this way.

Sunken City

At the beginning of your upkeep, sacrifice Sunken City unless you pay {U}{U}.
Blue creatures get +1/+1.

Vodalian Knights

First strike
Vodalian Knights can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Vodalian Knights.
{U}: Vodalian Knights gains flying until end of turn.

True-Name Nemesis

As True-Name Nemesis enters, choose a player.
True-Name Nemesis has protection from the chosen player.

Peer Pressure

Choose a creature type. If you control more creatures of that type than each other player, you gain control of all creatures of that type. (This effect lasts indefinitely.)

Ponder

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

Sea Scryer

Mystic Confluence

Choose three. You may choose the same mode more than once.
• Counter target spell unless its controller pays {3}.
• Return target creature to its owner's hand.
• Draw a card.

Lonely Sandbar

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

Rishadan Dockhand

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

Lingering Mirage

Enchant land
Enchanted land is an Island.
Cycling {2} ({2}, Discard this card: Draw a card.)

Saprazzan Bailiff

When Saprazzan Bailiff enters, exile all artifact and enchantment cards from all graveyards.
When Saprazzan Bailiff leaves the battlefield, return all artifact and enchantment cards from all graveyards to their owners' hands.

Crown of Ascension

Enchant creature
Enchanted creature has flying.
Sacrifice Crown of Ascension: Enchanted creature and other creatures that share a creature type with it gain flying until end of turn.

Mana Short

Tap all lands target player controls and that player loses all unspent mana.

Rootwater Matriarch

{T}: Gain control of target creature for as long as that creature is enchanted.

Lat-Nam's Legacy

Shuffle a card from your hand into your library. If you do, draw two cards at the beginning of the next turn's upkeep.

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.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Remand

Counter target spell. If that spell is countered this way, put it into its owner's hand instead of into that player's graveyard.
Draw a card.

Talrand, Sky Summoner

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

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.

Erosion

Enchant land
At the beginning of the upkeep of enchanted land's controller, destroy that land unless that player pays {1} or 1 life.

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.

Coral Fighters

Whenever Coral Fighters attacks and isn't blocked, look at the top card of defending player's library. You may put that card on the bottom of that player's library.

Vodalian Mage

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

Svyelunite Priest

{U}{U}, {T}: Target creature gains shroud until end of turn. Activate only during your upkeep. (It can't be the target of spells or abilities.)

Overtaker

{3}{U}, {T}, Discard a card: Untap target creature and gain control of it until end of turn. That creature gains haste until end of turn.

Sky Diamond

Seafloor Debris

Seafloor Debris enters tapped.
{T}: Add {U}.
{T}, Sacrifice Seafloor Debris: Add one mana of any color.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Coral Atoll

Coral Atoll enters tapped.
When Coral Atoll enters, sacrifice it unless you return an untapped Island you control to its owner's hand.
{T}: Add {C}{U}.

Saprazzan Legate

If an opponent controls a Mountain and you control an Island, you may cast this spell without paying its mana cost.
Flying

Phantasmal Terrain

Enchant land
As Phantasmal Terrain enters, choose a basic land type.
Enchanted land is the chosen type.

Reef Shaman

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

Sol Ring

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.

Telepathy

Your opponents play with their hands revealed.

Merfolk Looter

Merseine

Enchant creature
Merseine enters with three net counters on it.
Enchanted creature doesn't untap during its controller's untap step if Merseine has a net counter on it.
Pay enchanted creature's mana cost: Remove a net counter from Merseine. Only the controller of the enchanted creature may activate this ability.

Remote Isle

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

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}.)

Saprazzan Skerry

Saprazzan Skerry enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from Saprazzan Skerry: Add {U}{U}. If there are no depletion counters on Saprazzan Skerry, sacrifice it.

Rootwater Shaman

You may cast Aura spells with enchant creature as though they had flash.

High Tide

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

Inevitable Betrayal

Suspend 3—{1}{U}{U} (Rather than cast this card from your hand, pay {1}{U}{U} 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.)
Search target opponent's library for a creature card and put that card onto the battlefield under your control. Then that player shuffles.

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.