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.

{T}: Add {C}.

{1}, {T}: Until end of turn, creatures your opponents control lose hexproof and shroud and can't have hexproof or shroud.

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)

Return target nonland permanent to its owner's hand. If this spell was kicked, draw a card.

Return target permanent to its owner's hand.

Draw three cards, then put two cards from your hand on top of your library in any order.

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 one mana of any color in your commander's color identity.

Level up {1} ({1}: Put a level counter on this. Level up only as a sorcery.)

LEVEL 2-3

3/3

Flying

LEVEL 4+

4/4

Flying

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

Whenever an opponent shuffles their library, you may put a +1/+1 counter on Cosi's Trickster.

Counter target spell.

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.)

Counter target spell. If an artifact or creature spell is countered this way, put that card onto the battlefield under your control instead of into its owner's graveyard.

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

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

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 creature enters the battlefield under your control, you may pay {1}. If you do, put a +1/+1 counter on that creature.

{5}{G}, Sacrifice Durable Handicraft: Put a +1/+1 counter on each creature you control.

{U}{U}, {T}: Gain control of target legendary permanent. (This effect lasts indefinitely.)

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

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}.)

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

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.

Halimar Depths enters the battlefield tapped.

When Halimar Depths enters the battlefield, look at the top three cards of your library, then put them back in any order.

{T}: Add {U}.

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}.

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}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

When Jade Bearer enters the battlefield, put a +1/+1 counter on another target Merfolk you control.

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.

Llanowar Reborn enters the battlefield tapped.

{T}: Add {G}.

Graft 1 (This land enters the battlefield with a +1/+1 counter on it. Whenever a creature enters the battlefield, you may move a +1/+1 counter from this land onto it.)

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.

Lumbering Falls enters the battlefield tapped.

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

{2}{G}{U}: Lumbering Falls becomes a 3/3 green and blue Elemental creature with hexproof until end of turn. It's still a land.

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.)

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

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.

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

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

At the beginning of your end step, untap all Merfolk you control.

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.

Hideaway 4 (When this land enters the battlefield, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)

Mosswort Bridge enters the battlefield tapped.

{T}: Add {G}.

{G}, {T}: You may play the exiled card without paying its mana cost if creatures you control have total power 10 or greater.

Destroy target artifact or enchantment.

Destroy target artifact or enchantment. Its controller gains 4 life.

{T}: Add {C}.

{G}{U}, {T}: Put a +1/+1 counter on each creature that entered the battlefield this turn.

{T}: Add {C}.

{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Scry 1.

Draw a card.

Oran-Rief, the Vastwood enters the battlefield tapped.

{T}: Add {G}.

{T}: Put a +1/+1 counter on each green creature that entered the battlefield this turn.

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.)

Look at the top three cards of your library, then put them back in any order. You may shuffle.

Draw a card.

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

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.

You have no maximum hand size.

{T}: Add {C}.

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

{T}: Add {C}.

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

{U}: Rootwater Thief gains flying until end of turn.

Whenever Rootwater Thief deals combat damage to a player, you may pay {2}. If you do, search that player's library for a card and exile it, then the player shuffles.

Whenever Saprazzan Heir becomes blocked, you may draw three cards.

Whenever Scroll Thief deals combat damage to a player, draw a card.

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

Sacrifice Seal of Primordium: Destroy target artifact or enchantment.

Draw a card. Scry 2.

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 Growth Chamber enters the battlefield tapped.

When Simic Growth Chamber enters the battlefield, return a land you control to its owner's hand.

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

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)

I, II -- Until your next turn, creatures you control gain "{T}: Add one mana of any color."

III -- Put a +1/+1 counter on each creature you control. Those creatures gain vigilance, trample, and indestructible until end of turn.

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

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.

Temple of Mystery enters the battlefield tapped.

When Temple of Mystery enters the battlefield, scry 1.

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

({U/P} can be paid with either {U} or 2 life.)

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

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.

Counter target spell unless its controller pays {X}, where X is your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Thornwood Falls enters the battlefield tapped.

When Thornwood Falls enters the battlefield, you gain 1 life.

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

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

When Tidebinder Mage enters the battlefield, tap target red or green creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Tidebinder Mage.

When Tishana's Wayfinder 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.)

As True-Name Nemesis enters the battlefield, choose a player.

True-Name Nemesis has protection from the chosen player.

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.

Return target creature to its owner's hand. Its controller loses 1 life.

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

Vivid Creek enters the battlefield tapped with two charge counters on it.

{T}: Add {U}.

{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.

Vivid Grove enters the battlefield tapped with two charge counters on it.

{T}: Add {G}.

{T}, Remove a charge counter from Vivid Grove: Add one mana of any color.

Devoid (This card has no color.)

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Return target nonland permanent to its owner's hand.

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

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

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

Woodland Stream enters the battlefield tapped.

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