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.)

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.

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

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.

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.

As Metallic Mimic enters the battlefield, choose a creature type. Metallic Mimic is the chosen type in addition to its other types. Each other creature you control of the chosen type enters the battlefield with an additional +1/+1 counter on it.

Merfolk and Druid cards in your graveyard have retrace. (You may cast cards with retrace from your graveyard by discarding a land card in addition to paying their other costs.)

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.

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.

Flash When Singer of Swift Rivers enters the battlefield, put a shield counter on another target creature you control. (If it would be dealt damage or destroyed, remove a shield counter from it instead.) You may cast Merfolk spells as though they had flash.

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.

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.

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

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.

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.

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.

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

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

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

Flying Creatures you control have "Whenever this creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability."

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.

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

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}.)

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.) Equip {1}

{T}: Add {C}. {G}{U}, {T}: You may cast spells this turn as though they had flash.

({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.

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

Dreamroot Cascade enters the battlefield tapped unless you control two or more other lands. {T}: Add {G} or {U}.

({T}: Add {G}.)

Hinterland Harbor enters the battlefield tapped unless you control a Forest or an Island. {T}: Add {G} or {U}.

({T}: Add {U}.)

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

Hideaway 4 (When this land enters the battlefield, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.) Mosswort Bridge enters the battlefield tapped. {T}: Add {G}. {G}, {T}: You may play the exiled card without paying its mana cost if creatures you control have total power 10 or greater.

{T}: Add {C}. {2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

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.)

Rejuvenating Springs enters the battlefield tapped unless you have two or more opponents. {T}: Add {G} or {U}.

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

{T}: Add {C}. {4}, {T}: Target creature can't be blocked this turn.

As Secluded Courtyard 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 or activate an ability of a creature source of the chosen type.

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}.

As Unclaimed Territory 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.

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}.

{T}, Pay 1 life: Add {G} or {U}. {1}, {T}, Sacrifice Waterlogged Grove: Draw a card.

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

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

Creatures you control have "{T}: Add one mana of any color."

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

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

{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.

Return all attacking creatures to their owner's hand.

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

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

Counter target spell.

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.")

Counter target spell. If the spell is countered this way, exile it with three time counters on it instead of putting it into its owner's graveyard. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, they remove a time counter. When the last is removed, they may play it without paying its mana cost. If it's a creature, it has haste.)

Return all creatures to their owners' hands.

Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token. Tap seven untapped Merfolk you control: Counter target spell.

You may exile a blue card from your hand rather than pay this spell's mana cost. Change the target of target spell with a single target.

Counter target noncreature spell.

Choose two — • Return target creature or planeswalker to its owner's hand. • Counter target artifact or enchantment spell. • Put two +1/+1 counters on target creature. • Target player shuffles up to three target cards from their graveyard into their library.

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

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

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

Flash Other Merfolk you control get +1/+1. Sacrifice a Merfolk: Counter target noncreature spell unless its controller pays {1}.

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.

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

Creatures don't untap during their controllers' untap steps. Whenever a creature enters the battlefield, untap all creatures.

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

Creatures you control have hexproof. {1}{G}: Regenerate target creature. (The next time it would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, counter that spell if it has the same mana value as the revealed card.

Landfall — Whenever a land enters the battlefield under your control, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

At the beginning of each player's upkeep, that player puts a flood counter on target non-Island land they control of their choice. That land is an Island for as long as it has a flood counter on it. At the beginning of each end step, if all lands on the battlefield are Islands, remove all flood counters from them.

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

{T}, Tap an untapped creature you control: Add one mana of any color.

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

Land creatures you control have flying. Whenever a land enters the battlefield under your control, if you control seven or more lands, up to one target land you control becomes a 3/3 Elemental creature with haste. It's still a land.

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.)