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.

Whenever another Merfolk you control enters, put a +1/+1 counter on target Merfolk 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.)

{1}{G}{U}: Put a +1/+1 counter on target creature you control. Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on this enchantment. At the beginning of your upkeep, if this enchantment has twenty or more growth counters on it, you win the game.

Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith. At the beginning of combat on your turn, if The Ozolith has counters on it, you may move all counters from The Ozolith onto target creature.

When Kiora enters, draw two cards, then discard two cards. Threshold — Whenever Kiora attacks, if there are seven or more cards in your graveyard, you may create Scion of the Deep, a legendary 8/8 blue Octopus 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 this creature, 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.

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.

As this enchantment enters, choose a creature type. Whenever a creature you control of the chosen type enters or attacks, draw a card.

Tap another untapped Merfolk you control: Kumena 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 this creature enters, 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}.

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

Svyelun 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 you control enters, you gain 1 life and draw a card.

This spell costs {X} less to cast, where X is the greatest power among creatures you control. {T}: Add {G}{G}. You gain 2 life. Whenever a nontoken creature you control enters, put a +1/+1 counter on it and draw a card.

Indestructible When The One Ring enters, if you cast it, you gain protection from everything until your next turn. At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring. {T}: Put a burden counter on The One Ring, then draw a card for each burden counter on The One Ring.

{4}: Scry 1, then reveal the top card of your library. If it's a land card, put it onto the battlefield tapped. Otherwise, draw a card. Partner (You can have two commanders if both have partner.)

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.) Whenever a creature you control with a +1/+1 counter on it dies, draw a card.

Whenever a creature you control enters, draw a card if its power is 3 or greater. Otherwise, put two +1/+1 counters on it.

When this creature enters, shuffle the cards from your hand into your library, then draw that many cards.

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

Haste When this creature enters, creatures you control gain trample and get +X/+X until end of turn, where X is the number of creatures you control.

{T}: Add {C}{C}. This land deals 2 damage to you.

{T}: Add {G}. Channel — {1}{G}, Discard this card: 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.

({T}: Add {G} or {U}.) As this land enters, you may pay 2 life. If you don't, it enters tapped.

As this land enters, 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.

This land enters tapped unless you control two or more other lands. {T}: Add {G} or {U}.

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

{T}, Sacrifice this land: 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.

({T}: Add {G}.)

({T}: Add {G} or {U}.) This land enters tapped. When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

This land enters tapped unless you control a Forest or an Island. {T}: Add {G} or {U}.

({T}: Add {U}.)

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

{T}, Pay 1 life, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield, then shuffle.

This land enters tapped unless you have two or more opponents. {T}: Add {G} or {U}.

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

This land enters tapped. When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.) {T}: Add {G} or {U}.

As Three Tree City enters, choose a creature type. {T}: Add {C}. {2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

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

{T}: Add {C}. {T}: Add {G} or {U}. This land deals 1 damage to you.

Prevent all combat damage that would be dealt this turn.

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

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.

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

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

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.

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

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.

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

{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.

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.")

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

Flash Vigilance When this creature enters, tap target creature an opponent controls and put a stun counter on it. {1}{U}, {T}: Shuffle this creature and target creature with a stun counter on it into their owners' libraries.

You may cast this card as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.) When this creature enters, you may return target tapped creature an opponent controls to its owner's hand.

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Counter target artifact, creature, or planeswalker spell. Its controller creates a 2/2 blue Bird creature token with flying.

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

As this artifact enters, choose a creature type. Creature spells you cast of the chosen type cost {1} less to cast. At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

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

Enchant land When this Aura enters, draw a card. Enchanted land is an Island.

Flying

{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery. (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.)