At the beginning of your upkeep, you may put a charge counter on Aether Vial.
{T}: You may put a creature card with mana value equal to the number of charge counters on Aether Vial from your hand onto the battlefield.
{U}
Aquitect's Will
Tribal Sorcery - Merfolk
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.
{2}
Arcane Signet
Artifact
{T}: Add one mana of any color in your commander's color identity.
{2}{U}
As Foretold
Enchantment
At the beginning of your upkeep, put a time counter on As Foretold.
Once each turn, you may pay {0} rather than pay the mana cost for a spell you cast with mana value X or less, where X is the number of time counters on As Foretold.
--
Ash Barrens
Land
{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)
{B}{G}
Assassin's Trophy
Instant
Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.
--
Barkchannel Pathway
Land
{T}: Add {G}.
--
Tidechannel Pathway
Land
{T}: Add {U}.
{G}
Birds of Paradise
Creature - Bird
Flying
{T}: Add one mana of any color.
0 /
1
{1}{G}
Bloom Tender
Creature - Elf Druid
{T}: For each color among permanents you control, add one mana of that color.
1 /
1
--
Breeding Pool
Land - Forest Island
({T}: Add {G} or {U}.)
As Breeding Pool enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.
{3}{G}
Cazur, Ruthless Stalker
Legendary Creature - Human Warrior
Partner with Ukkima, Stalking Shadow (When this creature enters the battlefield, target player may put Ukkima into their hand from their library, then shuffle.)
Whenever a creature you control deals combat damage to a player, put a +1/+1 counter on that creature.
3 /
3
{3}
Chromatic Lantern
Artifact
Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.
--
City of Brass
Land
Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.
--
Clearwater Pathway
Land
{T}: Add {U}.
--
Murkwater Pathway
Land
{T}: Add {B}.
{5}
Coat of Arms
Artifact
Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)
{1}{G/U}{G/U}
Cold-Eyed Selkie
Creature - Merfolk Rogue
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.
1 /
1
--
Command Tower
Land
{T}: Add one mana of any color in your commander's color identity.
{U}{U}
Coralhelm Commander
Creature - Merfolk Soldier
Level up {1} ({1}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 2-3
3/3
Flying
LEVEL 4+
4/4
Flying
Other Merfolk creatures you control get +1/+1.
2 /
2
{1}{B}
Cover of Darkness
Enchantment
As Cover of Darkness enters the battlefield, choose a creature type.
Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)
{1}{G}
Cryptolith Rite
Enchantment
Creatures you control have "{T}: Add one mana of any color."
{1}{U}
Cyclonic Rift
Instant
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.")
--
Darkwater Catacombs
Land
{1}, {T}: Add {U}{B}.
{5}{U}
Deepchannel Mentor
Creature - Merfolk Rogue
Blue creatures you control can't be blocked.
2 /
2
{2}{U}
Deeproot Waters
Enchantment
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.)
{1}{G}{U}
Edric, Spymaster of Trest
Legendary Creature - Elf Rogue
Whenever a creature deals combat damage to one of your opponents, its controller may draw a card.
2 /
2
{3}{U}{U}
Empress Galina
Legendary Creature - Merfolk Noble
{U}{U}, {T}: Gain control of target legendary permanent. (This effect lasts indefinitely.)
1 /
3
{U}
Enclave Cryptologist
Creature - Merfolk Wizard
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.
0 /
1
--
Evolving Wilds
Land
{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
--
Exotic Orchard
Land
{T}: Add one mana of any color that a land an opponent controls could produce.
--
Fabled Passage
Land
{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.
--
Flooded Grove
Land
{T}: Add {C}.
{G/U}, {T}: Add {G}{G}, {G}{U}, or {U}{U}.
--
Forest
Basic Land - Forest
({T}: Add {G}.)
--
Forest
Basic Land - Forest
({T}: Add {G}.)
{1}{B}{B}{B}
Grave Pact
Enchantment
Whenever a creature you control dies, each other player sacrifices a creature.
{2}{G}
Harvest Season
Sorcery
Search your library for up to X basic land cards, where X is the number of tapped creatures you control, put those cards onto the battlefield tapped, then shuffle.
{3}{U}
Herald of Secret Streams
Creature - Merfolk Warrior
Creatures you control with +1/+1 counters on them can't be blocked.
2 /
3
{1}{G}
Heroic Intervention
Instant
Permanents you control gain hexproof and indestructible until end of turn.
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
{3}{U}{U}
Kindred Discovery
Enchantment
As Kindred Discovery enters the battlefield, choose a creature type.
Whenever a creature you control of the chosen type enters the battlefield or attacks, draw a card.
{5}{B}{B}
Kindred Dominance
Sorcery
Choose a creature type. Destroy all creatures that aren't of the chosen type.
{G}{U}
Kiora's Follower
Creature - Merfolk
{T}: Untap another target permanent.
2 /
2
{1}{U}{U}
Kopala, Warden of Waves
Legendary Creature - Merfolk Wizard
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.
2 /
2
{1}{G}{U}
Kumena, Tyrant of Orazca
Legendary Creature - Merfolk Shaman
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.
2 /
4
{U}{U}
Lord of Atlantis
Creature - Merfolk
Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)
2 /
2
--
Mana Confluence
Land
{T}, Pay 1 life: Add one mana of any color.
{3}{U}
Master of Waves
Creature - Merfolk Wizard
Protection from red
Elemental creatures you control get +1/+1.
When Master of Waves enters the battlefield, 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.)
2 /
1
{U}{U}
Master of the Pearl Trident
Creature - Merfolk
Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)
2 /
2
{1}{U}
Merfolk Looter
Creature - Merfolk Rogue
{T}: Draw a card, then discard a card.
1 /
1
{G}{U}
Merfolk Mistbinder
Creature - Merfolk Shaman
Other Merfolk you control get +1/+1.
2 /
2
{1}{U}{U}
Merfolk Sovereign
Creature - Merfolk Noble
Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.
2 /
2
{1}{U}
Merrow Commerce
Tribal Enchantment - Merfolk
At the beginning of your end step, untap all Merfolk you control.
{2}{U}
Merrow Reejerey
Creature - Merfolk Soldier
Other Merfolk creatures you control get +1/+1.
Whenever you cast a Merfolk spell, you may tap or untap target permanent.
2 /
2
{U}
Mist-Cloaked Herald
Creature - Merfolk Warrior
Mist-Cloaked Herald can't be blocked.
1 /
1
--
Misty Rainforest
Land
{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.
{1}{B}
Night's Whisper
Sorcery
You draw two cards and you lose 2 life.
--
Opulent Palace
Land
Opulent Palace enters the battlefield tapped.
{T}: Add {B}, {G}, or {U}.
{2}{B}
Painful Truths
Sorcery
Converge -- You draw X cards and you lose X life, where X is the number of colors of mana spent to cast this spell.
--
Polluted Delta
Land
{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.
{1}{G}{U}
Primal Empathy
Enchantment
At the beginning of your upkeep, draw a card if you control a creature with the greatest power among creatures on the battlefield. Otherwise, put a +1/+1 counter on a creature you control.
{2}{G}{G}{U}{U}
Prime Speaker Zegana
Legendary Creature - Merfolk Wizard
Prime Speaker Zegana enters the battlefield with X +1/+1 counters on it, where X is the greatest power among other creatures you control.
When Prime Speaker Zegana enters the battlefield, draw cards equal to its power.
1 /
1
--
Prismatic Vista
Land
{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.
{2}{B}
Read the Bones
Sorcery
Scry 2, then draw two cards. You lose 2 life.
{4}{U}
Reflections of Littjara
Enchantment
As Reflections of Littjara enters the battlefield, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)
{1}{U}
Sea Scryer
Creature - Merfolk Wizard
{T}: Add {C}.
{1}, {T}: Add {U}.
1 /
1
{2}{U}{U}
Seafloor Oracle
Creature - Merfolk Wizard
Whenever a Merfolk you control deals combat damage to a player, draw a card.
2 /
3
{5}{B}{B}
Sheoldred, Whispering One
Legendary Creature - Phyrexian Praetor
Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.
At the beginning of each opponent's upkeep, that player sacrifices a creature.
6 /
6
{1}{U}
Spreading Seas
Enchantment - Aura
Enchant land
When Spreading Seas enters the battlefield, draw a card.
Enchanted land is an Island.
{1}{G}
Steely Resolve
Enchantment
As Steely Resolve enters the battlefield, choose a creature type.
Creatures of the chosen type have shroud. (They can't be the targets of spells or abilities.)
{1}{U}
Stonybrook Banneret
Creature - Merfolk Wizard
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.
1 /
1
{5}{U}{U}{U}
Stormtide Leviathan
Creature - Leviathan
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.
8 /
8
{1}{U}{U}
Streambed Aquitects
Creature - Merfolk Scout
{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.
2 /
3
{B}{G}{U}
Sultai Charm
Instant
Choose one --
• Destroy target monocolored creature.
• Destroy target artifact or enchantment.
• Draw two cards, then discard a card.
--
Sunken Ruins
Land
{T}: Add {C}.
{U/B}, {T}: Add {U}{U}, {U}{B}, or {B}{B}.
{1}{U}{U}
Svyelun of Sea and Sky
Legendary Creature - Merfolk God
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}.)
3 /
4
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
--
Swamp
Basic Land - Swamp
({T}: Add {B}.)
{2}
Sword of the Animist
Legendary Artifact - Equipment
Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip {2}
{1}{G}
Sylvan Library
Enchantment
At the beginning of your draw step, you may draw two additional cards. If you do, choose two cards in your hand drawn this turn. For each of those cards, pay 4 life or put the card on top of your library.
--
Tarnished Citadel
Land
{T}: Add {C}.
{T}: Add one mana of any color. Tarnished Citadel deals 3 damage to you.
--
Terramorphic Expanse
Land
{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
{1}{U}
Thieving Skydiver
Creature - Merfolk Rogue
Kicker {X}. X can't be 0. (You may pay an additional {X} as you cast this spell.)
Flying
When Thieving Skydiver enters the battlefield, if it was kicked, gain control of target artifact with mana value X or less. If that artifact is an Equipment, attach it to Thieving Skydiver.
2 /
1
{U}
Tidal Warrior
Creature - Merfolk Warrior
{T}: Target land becomes an Island until end of turn.
1 /
1
{U}
Triton Shorestalker
Creature - Merfolk Rogue
Triton Shorestalker can't be blocked.
1 /
1
--
Tropical Island
Land - Forest Island
({T}: Add {G} or {U}.)
{1}{U}{U}
True-Name Nemesis
Creature - Merfolk Rogue
As True-Name Nemesis enters the battlefield, choose a player.
True-Name Nemesis has protection from the chosen player.
3 /
1
{1}{U}{B}
Ukkima, Stalking Shadow
Legendary Creature - Whale Wolf
Partner with Cazur, Ruthless Stalker (When this creature enters the battlefield, target player may put Cazur into their hand from their library, then shuffle.)
Ukkima, Stalking Shadow can't be blocked.
When Ukkima leaves the battlefield, it deals X damage to target player and you gain X life, where X is its power.
2 /
2
--
Underground River
Land
{T}: Add {C}.
{T}: Add {U} or {B}. Underground River deals 1 damage to you.
--
Underground Sea
Land - Island Swamp
({T}: Add {U} or {B}.)
--
Urborg, Tomb of Yawgmoth
Legendary Land
Each land is a Swamp in addition to its other land types.
{5}
Vanquisher's Banner
Artifact
As Vanquisher's Banner enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.
--
Verdant Catacombs
Land
{T}, Pay 1 life, Sacrifice Verdant Catacombs: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.
{3}{G}{G}{G}
Vigor
Creature - Elemental Incarnation
Trample
If damage would be dealt to another creature you control, prevent that damage. Put a +1/+1 counter on that creature for each 1 damage prevented this way.
When Vigor is put into a graveyard from anywhere, shuffle it into its owner's library.
6 /
6
--
Waterlogged Grove
Land
{T}, Pay 1 life: Add {G} or {U}.
{1}, {T}, Sacrifice Waterlogged Grove: Draw a card.
--
Watery Grave
Land - Island Swamp
({T}: Add {U} or {B}.)
As Watery Grave enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.
{3}{G}
World Shaper
Creature - Merfolk Shaman
Whenever World Shaper attacks, you may mill three cards.
When World Shaper dies, return all land cards from your graveyard to the battlefield tapped.
3 /
3
--
Yavimaya Coast
Land
{T}: Add {C}.
{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.
--
Yavimaya, Cradle of Growth
Legendary Land
Each land is a Forest in addition to its other land types.
--
Zagoth Triome
Land - Swamp Forest Island
({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters the battlefield tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)
{2}{G}{U}
Zegana, Utopian Speaker
Legendary Creature - Merfolk Wizard
When Zegana, Utopian Speaker enters the battlefield, if you control another creature with a +1/+1 counter on it, draw a card.
{4}{G}{U}: Adapt 4. (If this creature has no +1/+1 counters on it, put four +1/+1 counters on it.)
Each creature you control with a +1/+1 counter on it has trample.