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

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.

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}.

({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.

Castle Vantress enters the battlefield tapped unless you control an Island.

{T}: Add {U}.

{2}{U}{U}, {T}: Scry 2.

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.

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.

Counter target spell.

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.

Blue creatures you control can't be blocked.

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.)

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Untap all nonland permanents you control.

Counter target creature spell. Put a +1/+1 counter on up to one target creature you control.

Whenever Fallowsage becomes tapped, you may 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.

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

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.

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

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

As Icon of Ancestry enters the battlefield, choose a creature type.

Creatures you control of the chosen type get +1/+1.

{3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

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.)

({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 {C}.

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

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."

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.

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.

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 upkeep, scry 1.

Whenever you cast a creature spell, you may pay {G}. If you do, draw a card.

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

Protection from red

Elemental creatures you control get +1/+1.

When Master of Waves enters the battlefield, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

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.

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.

Flash

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

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.

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.

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

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

Untap all green and/or blue creatures you control during each other player's untap step.

{T}: Add {C}.

{1}: Mutavault becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Counter target noncreature spell.

+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.

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.)

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

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.

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

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

You have no maximum hand size.

{T}: Add {C}.

When Rishkar, Peema Renegade enters the battlefield, put a +1/+1 counter on each of up to two target creatures.

Each creature you control with a counter on it has "{T}: Add {G}."

{T}: Add {C}.

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

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.

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.

Choose one --

• Target creature gets +3/+3 until end of turn.

• Permanents you control gain hexproof until end of turn.

• Return target creature to its owner's hand.

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

Tap all creatures target player controls. Those creatures don't untap during that player's next untap step.

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

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

Flash

When Swift Warden enters the battlefield, target Merfolk you control gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Counter target activated ability, triggered ability, or legendary spell.

Temple of Mystery enters the battlefield tapped.

When Temple of Mystery enters the battlefield, scry 1.

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

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.

Indestructible

As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

At the beginning of your upkeep, scry 1.

{1}{U}: Target creature you control can't be blocked this turn.

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 enters the battlefield under your control, put a +1/+1 counter on it and draw a 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.

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.

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.

Counter target noncreature spell. Untap up to three lands.

Trample

If damage would be dealt to another creature you control, prevent that damage. Put a +1/+1 counter on that creature for each 1 damage prevented this way.

When Vigor is put into a graveyard from anywhere, shuffle it into its owner's library.

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

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

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

{T}: Add {C}.

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