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.

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

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

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

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.

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.)

{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.

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.

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.) Creatures you control have "Whenever one or more counters are put on this creature for the first time each turn, draw a card."

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}: Draw a card, then discard a card.

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

As an additional cost to cast this spell, reveal a Merfolk card from your hand or pay {3}. When Silvergill Adept enters the battlefield, draw a card.

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.

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.

{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.)

Gray Harbor Merfolk can't be blocked. Gray Harbor Merfolk gets +2/+0 as long as you control a commander that's a creature or planeswalker.

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

Whenever a creature you control explores, Merfolk Cave-Diver gets +1/+0 until end of turn and can't be blocked this turn.

Mist-Cloaked Herald can't be blocked.

River Sneak can't be blocked. Whenever another Merfolk enters the battlefield under your control, River Sneak gets +1/+1 until end of turn.

Kicker {1} (You may pay an additional {1} as you cast this spell.) When Tide Shaper enters the battlefield, if it was kicked, target land becomes an Island for as long as Tide Shaper remains on the battlefield. Tide Shaper gets +1/+1 as long as an opponent controls an Island.

Triton Shorestalker can't be blocked.

As True-Name Nemesis enters the battlefield, choose a player. True-Name Nemesis has protection from the chosen player.

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.)

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.)

Vigilance Whenever Sentinel of the Nameless City enters the battlefield or attacks, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

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.

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep. You draw a card at the beginning of the next turn's upkeep.

Counter target spell.

Return all noncreature, nonland permanents to their owners' hands.

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

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

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

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}: Add {G} or {U}.) As Breeding Pool enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

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.

{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 one mana of any color that a land an opponent controls could produce.

{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.

({T}: Add {G}.)

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

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

({T}: Add {U}.)

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 {G} or {U}.) Rimewood Falls enters the battlefield tapped.

Svyelunite Temple enters the battlefield tapped. {T}: Add {U}. {T}, Sacrifice Svyelunite Temple: Add {U}{U}.

{T}: Add {C}. {1}, {T}, Sacrifice Tectonic Edge: Destroy target nonbasic land. Activate only if an opponent controls four or more lands.

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.

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

Whenever Deeproot Wayfinder deals combat damage to a player or battle, surveil 1, then you may return a land card from your graveyard to the battlefield tapped. (To surveil 1, look at the top card of your library. You may put that card into your graveyard.)

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

{T}: Untap another target permanent.

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.

{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.

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

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

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.)

Choose a creature type. Draw a card for each permanent you control of that type.

When Jungleborn Pioneer enters the battlefield, create a 1/1 blue Merfolk creature token with hexproof. (It can't be the target of spells or abilities your opponents control.)

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.

At the beginning of your end step, you may reveal your hand and put all land cards from it onto the battlefield. If you do, discard your hand.

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.)

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.)

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 Sage of the Falls or another non-Human creature enters the battlefield under your control, you may draw a card. If you do, discard a card.

Shaper Apprentice has flying as long as you control another Merfolk.

You may play up to three additional lands this turn.

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.