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.

{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.

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

{1}{U}, {T}: Creatures your opponents control attack this turn if able.

Botanical Sanctum enters the battlefield tapped unless you control two or fewer other lands.

{T}: Add {G} or {U}.

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

{T}: Add {C}.

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

{4}, {T}, Sacrifice Cave of Temptation: Put two +1/+1 counters on target creature. Activate only as a sorcery.

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}{G}, {T}: This turn, each creature you control enters the battlefield with an additional +1/+1 counter on it.

{1}{U}, {T}: Move a +1/+1 counter from target creature you control onto another target creature you control.

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

Coral Atoll enters the battlefield tapped.

When Coral Atoll enters the battlefield, sacrifice it unless you return an untapped Island you control to its owner's hand.

{T}: Add {C}{U}.

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.

Whenever an opponent shuffles their library, you may put a +1/+1 counter on Cosi's Trickster.

Blue creatures you control can't be blocked.

Whenever you cast a noncreature spell, put a +1/+1 counter on Deeproot Champion.

Whenever another Merfolk enters the battlefield under your control, put a +1/+1 counter on target Merfolk you control.

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.)

Dreamroot Cascade enters the battlefield tapped unless you control two or more other lands.

{T}: Add {G} or {U}.

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

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.

{T}: Add {C}.

{G/U}, {T}: Add {G}{G}, {G}{U}, or {U}{U}.

When Forerunner of the Heralds enters the battlefield, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.

Whenever another Merfolk enters the battlefield under your control, put a +1/+1 counter on Forerunner of the Heralds.

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control. Then if that creature has three or more +1/+1 counters on it, transform Hadana's Climb.

(Transforms from Hadana's Climb.)

{T}: Add one mana of any color.

{1}{G}{U}, {T}: Target creature you control gains flying and gets +X/+X until end of turn, where X is its power.

Halimar Depths enters the battlefield tapped.

When Halimar Depths enters the battlefield, look at the top three cards of your library, then put them back in any order.

{T}: Add {U}.

Creatures you control with +1/+1 counters on them can't be blocked.

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

When Jadelight Ranger enters the battlefield, it explores, then it explores again. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard. Then repeat this process.)

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.

+1: Untap up to one target creature and up to one target land.

-2: Reveal the top four cards of your library. You may put a creature card and/or a land card from among them into your hand. Put the rest into your graveyard.

-8: You get an emblem with "Whenever a creature enters the battlefield under your control, you may have it fight target creature." Then create three 8/8 blue Octopus creature tokens.

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.

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)

At the beginning of your upkeep, each player draws a card. If you have the city's blessing, instead only you draw a card.

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.

Whenever Library Larcenist attacks, draw a card.

Littjara Mirrorlake enters the battlefield tapped.

{T}: Add {U}.

{2}{G}{G}{U}, {T}, Sacrifice Littjara Mirrorlake: Create a token that's a copy of target creature you control, except it enters the battlefield with an additional +1/+1 counter on it. Activate only as a sorcery.

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

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

When Merfolk Branchwalker enters the battlefield, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

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

Other Merfolk you control get +1/+1.

Flying

When Merfolk Skydiver enters the battlefield, put a +1/+1 counter on target creature you control.

{3}{G}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Other Merfolk creatures you control get +1/+1.

{T}: Target Merfolk creature can't be blocked this turn.

Flying

When Merfolk Wayfinder enters the battlefield, reveal the top three cards of your library. Put all Island cards revealed this way into your hand and the rest on the bottom of your library in any order.

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

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

When Merrow Harbinger enters the battlefield, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.

Other Merfolk creatures you control get +1/+1.

Whenever you cast a Merfolk spell, you may tap or untap target permanent.

{T}: Add {C}.

{2}, {T}: Each player draws a card.

Mist-Cloaked Herald can't be blocked.

Myriad Landscape enters the battlefield 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.

{T}: Add {C}.

{G}{U}, {T}: Put a +1/+1 counter on each creature that entered the battlefield this turn.

Path of Ancestry enters the battlefield tapped.

{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

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

Draw a card.

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.

{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.

({T}: Add {G} or {U}.)

Rimewood Falls enters the battlefield tapped.

River Sneak can't be blocked.

Whenever another Merfolk enters the battlefield under your control, River Sneak gets +1/+1 until end of turn.

Return all nonland permanents target player controls to their owner's hand.

Each other Wizard creature you control enters the battlefield with an additional +1/+1 counter on it.

{2}, Remove a +1/+1 counter from a creature you control: Draw a card.

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

Draw cards equal to the number of cards in your hand plus one. You have no maximum hand size for the rest of the game.

As Sea Gate, Reborn enters the battlefield, you may pay 3 life. If you don't, it enters the battlefield tapped.

{T}: Add {U}.

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

{3}, {T}: Search your library for a Merfolk permanent card, put it onto the battlefield, then shuffle.

{3}{G}: Put a +1/+1 counter on target creature.

{2}{U}, Remove a +1/+1 counter from a creature you control: Draw a card.

Evolve (Whenever a creature enters the battlefield under your control, 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.

Simic Growth Chamber enters the battlefield tapped.

When Simic Growth Chamber enters the battlefield, return a land you control to its owner's hand.

{T}: Add {G}{U}.

Simic Guildgate enters the battlefield tapped.

{T}: Add {G} or {U}.

Look at the top X cards of your library, where X is three plus the number of creatures in your party. Put three of those cards into your hand and the rest on the bottom of your library in a random order. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)

When Slinn Voda, the Rising Deep enters the battlefield, if it was kicked, return all creatures to their owners' hands except for Merfolk, Krakens, Leviathans, Octopuses, and Serpents.

Enchant land

When Spreading Seas enters the battlefield, draw a card.

Enchanted land is an Island.

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.

{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.

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

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}.)

Landfall -- Whenever a land enters the battlefield under your control, you gain 1 life and draw a card.

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

When Thassa's Oracle enters the battlefield, 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.)

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.

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

Tishana, Voice of Thunder's power and toughness are each equal to the number of cards in your hand.

You have no maximum hand size.

When Tishana enters the battlefield, draw a card for each creature you control.

Triton Shorestalker can't be blocked.

Whenever you cast an instant, sorcery, or Wizard spell, Umara Wizard gains flying until end of turn.

Umara Skyfalls enters the battlefield tapped.

{T}: Add {U}.

As Vineglimmer Snarl enters the battlefield, you may reveal a Forest or Island card from your hand. If you don't, Vineglimmer Snarl enters the battlefield tapped.

{T}: Add {G} or {U}.

When Vineshaper Mystic enters the battlefield, put a +1/+1 counter on each of up to two target Merfolk you control.

{G}{U}, {T}: Double the number of each kind of counter on target artifact, creature, or land.

Whenever a permanent you control becomes untapped, Wake Thrasher gets +1/+1 until end of turn.

Champion a Merfolk (When this enters the battlefield, 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.

Whenever World Shaper attacks, you may mill three cards.

When World Shaper dies, return all land cards from your graveyard to the battlefield tapped.

{T}: Add {C}.

{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.

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.