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.

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

{T}: Add {U}.

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

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

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.

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

Draw a card.

Whenever you cast a noncreature spell, put a +1/+1 counter on Deeproot Champion.

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.)

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Gain control of target creature with mana value X.

Counter target creature spell.

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

Frontier Bivouac enters the battlefield tapped.

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

Draw a card. You may put a land card from your hand onto the battlefield.

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.

(Transforms from Hadana's Climb.)

{T}: Add one mana of any color.

{1}{G}{U}, {T}: Target creature you control gains flying and gets +X/+X until end of turn, where X is its power.

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

({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}.)

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.)

{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.

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.

Counter target spell unless its controller pays {3}.

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.)

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.)

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.

{T}: Add {U}.

{U}, {T}: Untap target legendary permanent.

Mist-Cloaked Herald can't be blocked.

Destroy target artifact or enchantment.

Counter target noncreature spell.

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

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.

Put a +1/+1 counter on target creature and a +1/+1 counter on up to one target Merfolk.

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

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

{3}{G}: Put a +1/+1 counter on target creature.

{2}{U}, Remove a +1/+1 counter from a creature you control: 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.

Simic Guildgate enters the battlefield tapped.

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

Counter target noncreature spell unless its controller pays {2}.

Temple of Mystery enters the battlefield tapped.

When Temple of Mystery enters the battlefield, scry 1.

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

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

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