Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

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

{T}: Add {G}.

{T}: Add {U}.

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

{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.

{T}: Add {G}.

Channel -- {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

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

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

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.

({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.

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.

Descend 8 -- When you cast this spell, if there are eight or more permanent cards in your graveyard, copy this spell twice. You may choose new targets for the copies.

Return target permanent card from your graveyard to your hand. Exile Bygone Marvels.

As Cavern of Souls enters the battlefield, choose a creature type.

{T}: Add {C}.

{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

When Cenote Scout 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.)

Imprint -- When Chrome Mox enters the battlefield, you may exile a nonartifact, nonland card from your hand.

{T}: Add one mana of any of the exiled card's colors.

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.

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

Haste

When Craterhoof Behemoth enters the battlefield, creatures you control gain trample and get +X/+X until end of turn, where X is the number of creatures you control.

Sacrifice Cursecatcher: Counter target instant or sorcery spell unless its controller pays {1}.

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.")

At the beginning of combat on your turn, Deepfathom Echo explores. Then you may have it become a copy of another creature you control until end of turn. (To have this creature explore, 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.)

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

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

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

You may look at the top card of your library any time.

You may cast Merfolk spells from the top of your library.

Whenever you cast a Merfolk spell, you may pay {1}. If you do, create a 1/1 blue Merfolk creature token.

{T}: Add one mana of any color that a land an opponent controls could produce.

You may play an additional land on each of your turns.

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

If you control a commander, you may cast this spell without paying its mana cost.

Counter target noncreature spell.

{T}: Add {C}.

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

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.

Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.

Counter target spell.

At the beginning of combat on your turn, each Merfolk creature you control 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 the exploring creature, then put the card back or put it into your graveyard.)

Whenever Hakbal of the Surging Soul attacks, you may put a land card from your hand onto the battlefield. If you don't, draw a card.

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

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

Permanents you control gain hexproof and indestructible until end of turn.

Hinterland Harbor enters the battlefield tapped unless you control a Forest or an Island.

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

When Jadelight Spelunker enters the battlefield, it explores X times. (To have it explore, 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 that creature, then put the card back or put it into your graveyard.)

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

If one or more +1/+1 counters would be put on a permanent you control, that many plus one +1/+1 counters are put on that permanent instead.

{T}: Add X mana of any one color, where X is Kami of Whispered Hopes's power.

{T}: Add {C}.

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

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.

{T}: Untap another target permanent.

Reach

Modified creatures you control have trample. (Equipment, Auras you control, and counters are modifications.)

Whenever a modified creature you control deals combat damage to a player, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

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.

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

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.

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

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.)

Other Merfolk you control get +1/+1.

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

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

Flash

When Merfolk Trickster enters the battlefield, tap target creature an opponent controls. It loses all abilities until end of turn.

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

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

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.)

Sacrifice Mistcaller: Until end of turn, if a nontoken creature would enter the battlefield and it wasn't cast, exile it instead.

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

({T}: Add {U}.)

Mystic Sanctuary enters the battlefield tapped unless you control three or more other Islands.

When Mystic Sanctuary enters the battlefield untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Destroy target artifact or enchantment. Its controller gains 4 life.

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Whenever a creature you control explores a land card, you may put a land card from your hand onto the battlefield tapped.

Whenever a creature you control explores a nonland card, put a +1/+1 counter on Nicanzil, Current Conductor.

+2: Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

+1: Target artifact or creature loses all abilities and becomes a green Elk creature with base power and toughness 3/3.

-5: Exchange control of target artifact or creature you control and target creature an opponent controls with power 3 or less.

{T}: Add {U}.

Channel -- {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

If one or more +1/+1 counters would be put on an artifact or creature you control, that many plus one +1/+1 counters are put on it instead.

{1}{G}, {T}: Put a +1/+1 counter on target artifact or creature you control. Activate only as a sorcery.

Cycling {2} ({2}, Discard this card: Draw a card.)

Search your library for a sorcery card, reveal it, then shuffle and put that card on top.

Choose a creature type. Return all creatures that aren't of the chosen type to their owners' hands.

Changeling (This card is every creature type.)

As Realmwalker enters the battlefield, choose a creature type.

You may look at the top card of your library any time.

You may cast creature spells of the chosen type from the top of your library.

Rejuvenating Springs enters the battlefield tapped unless you have two or more opponents.

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

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

When River Herald Scout 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.)

Ward {2}

As Roaming Throne enters the battlefield, choose a creature type.

Roaming Throne is the chosen type in addition to its other types.

If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

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

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

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.

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}.)

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

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.

Search your library for a creature card, reveal it, then shuffle and put that card on top.

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

({U/P} can be paid with either {U} or 2 life.)

Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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

Whenever Thada Adel, Acquisitor deals combat damage to a player, search that player's library for an artifact card and exile it. Then that player shuffles. Until end of turn, you may play that card.

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.

Search your library for a Forest card, put it onto the battlefield, then shuffle.

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

Flash

When Tishana's Tidebinder enters the battlefield, counter up to one target activated or triggered ability. If an ability of an artifact, creature, or planeswalker is countered this way, that permanent loses all abilities for as long as Tishana's Tidebinder remains on the battlefield. (Mana abilities can't be targeted.)

When Topography Tracker enters the battlefield, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

If a creature you control would explore, instead it explores, then it explores again.

Until end of turn, creatures you control get +1/+1 and gain trample and infect. (Creatures with infect deal damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Return target permanent card from your graveyard to your hand. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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}.

Flash

Other Merfolk you control get +1/+1.

Sacrifice a Merfolk: Counter target noncreature spell unless its controller pays {1}.

{T}, Pay 1 life: Add {G} or {U}.

{1}, {T}, Sacrifice Waterlogged Grove: Draw a card.

Return each creature without a +1/+1 counter on it to its owner's hand.

Whenever a creature you control explores, put a +1/+1 counter on Wildgrowth Walker and you gain 3 life.

Search your library for a creature card, reveal it, then shuffle and put the card on top.

{T}: Add {C}.

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