Ezuri, Claw of Progress

{3}: Target player mills three cards.

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.

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.)

{U}: Blockade Runner can't be blocked this turn.

Devour 1 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with that many +1/+1 counters on it.)

Each other creature you control enters the battlefield with an additional X +1/+1 counters on it, where X is the number of +1/+1 counters on Bloodspore Thrinax.

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.

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.

{T}: Add {C}.

{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

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

When Contagion Engine enters the battlefield, put a -1/-1 counter on each creature target player controls.

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

Whenever a creature you control dies, put X +1/+1 counters on target creature you control, where X is the power of the creature that died.

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.)

As Door of Destinies enters the battlefield, choose a creature type.

Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.

Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Whenever a player casts a blue spell, you may pay {1}. If you do, target player mills two cards.

Tap an untapped Merfolk you control: Target player mills a card.

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Whenever a creature with power 2 or less enters the battlefield under your control, you get an experience counter.

At the beginning of combat on your turn, put X +1/+1 counters on another target creature you control, where X is the number of experience counters you have.

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

{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}.)

Flying

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control. Then if that creature has three or more +1/+1 counters on it, transform Hadana's Climb.

You may cast Harbinger of the Tides 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 Harbinger of the Tides enters the battlefield, you may return target tapped creature an opponent controls to its owner's hand.

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 an additional cost to cast this spell, sacrifice a land.

Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

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}.

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

({T}: Add {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 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.)

{T}: Untap another target permanent.

[+1]: Untap up to one target creature and up to one target land.

[−2]: Reveal the top four cards of your library. You may put a creature card and/or a land card from among them into your hand. Put the rest into your graveyard.

[−8]: You get an emblem with "Whenever a creature enters the battlefield under your control, you may have it fight target creature." Then create three 8/8 blue Octopus creature tokens.

[+1]: Until your next turn, prevent all damage that would be dealt to and dealt by target permanent an opponent controls.

[−1]: Draw a card. You may play an additional land this turn.

[−5]: You get an emblem with "At the beginning of your end step, create a 9/9 blue Kraken creature token."

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.

If Leyline of Lifeforce is in your opening hand, you may begin the game with it on the battlefield.

Creature spells can't be countered.

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

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.

Whenever an opponent casts a spell, reveal the top card of your library. If it's a creature card, put it onto the battlefield. Otherwise, you may put that card on the bottom of your library.

If you tap a permanent for mana, it produces twice as much of that mana instead.

Other Merfolk creatures you control 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 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.

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.

Mist-Cloaked Herald can't be blocked.

Devour 2 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it.)

At the beginning of your upkeep, create a 1/1 green Saproling creature token for each +1/+1 counter on Mycoloth.

Search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle. You gain 7 life.

[+2]: Scry 2.

[0]: Look at the top card of your library. If it's a land card or a creature card with mana value less than or equal to the number of loyalty counters on Nissa, Steward of Elements, you may put that card onto the battlefield.

[−6]: Untap up to two target lands you control. They become 5/5 Elemental creatures with flying and haste until end of turn. They're still lands.

{T}: Add {C}.

{1}, {T}: Add one mana of any color in your commander's color identity. If you spend this mana to cast your commander, it enters the battlefield with a number of additional +1/+1 counters on it equal to the number of times it's been cast from the command zone this game.

Until end of turn, creatures you control gain trample and get +X/+X, where X is the greatest power among creatures you control.

If one or more tokens would be created, twice that many of those tokens are created instead.

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

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.

Whenever you cast a creature spell, create a 3/3 green Beast creature token.

Whenever you cast a noncreature spell, put three +1/+1 counters on target creature you control.

Landfall — Whenever a land enters the battlefield under your control, you gain 3 life.

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.

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

{T}: Target land becomes the basic land type of your choice until end of turn.

Trample

When Regal Behemoth enters the battlefield, you become the monarch.

Whenever you tap a land for mana while you're the monarch, add an additional one mana of any color.

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

When Selkie Hedge-Mage enters the battlefield, if you control two or more Forests, you may gain 3 life.

When Selkie Hedge-Mage enters the battlefield, if you control two or more Islands, you may return target tapped creature to its owner's hand.

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

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.

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.

{T}: Target Merfolk creature gets +1/+1 and gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.)

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

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.

When Tempest Caller enters the battlefield, tap all creatures target opponent controls.

{T}: Add {C}{C}. Activate only if you control five or more lands.

Players can't activate planeswalkers' loyalty abilities.

At the beginning of your draw step, draw an additional card.

Spells you cast cost {1} less to cast.

Creatures you control get +1/+1.

{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.)

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 Vanquisher's Banner enters the battlefield, choose a creature type.

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

Whenever you cast a creature spell of the chosen type, draw a card.

When Vineshaper Mystic enters the battlefield, put a +1/+1 counter on each of up to two target Merfolk you control.

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

Trample

Whenever you tap a land for mana, add one mana of any type that land produced.

Whenever an opponent taps a land for mana, that land doesn't untap during its controller's next untap step.

Whenever a permanent you control becomes untapped, Wake Thrasher gets +1/+1 until end of turn.

{X}{G}{G}: Put X +1/+1 counters on target land you control. That land becomes a 0/0 Elemental creature with haste. It's still a land.

Whenever you tap a land for mana, add one mana of any type that land produced. (The types of mana are white, blue, black, red, green, and colorless.)

Whenever you cast a creature spell, draw a card.