{T}: Add {C}.

{G}{U}, {T}: You may cast spells this turn as though they had flash.

{T}: Add one mana of any color. Spend this mana only to cast a creature spell.

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.

At the beginning of your upkeep, return a permanent you control to its owner's hand.

Castle Garenbrig enters the battlefield tapped unless you control a Forest.

{T}: Add {G}.

{2}{G}{G}, {T}: Add six {G}. Spend this mana only to cast creature spells or activate abilities of creatures.

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 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.

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.

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

{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.

Whenever Fallowsage becomes tapped, you may draw a card.

{T}: Add {C}.

{2}, {T}, Sacrifice Field of Ruin: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

{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} for each creature you control.

Flying

{T}: Add {C}.

{T}, Sacrifice Ghost Quarter: Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

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.

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

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

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

{T}: Add {C}.

{T}: Each player gains control of all creatures they own.

Flash

If an opponent would draw a card except the first one they draw in each of their draw steps, instead you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Kinship -- At the beginning of your upkeep, you may look at the top card of your library. If it shares a creature type with Ink Dissolver, you may reveal it. If you do, each opponent mills three cards.

({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.

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.

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.

Kumena's Speaker gets +1/+1 as long as you control another Merfolk or an Island.

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.

Whenever Library Larcenist attacks, draw a card.

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

{U}: Manta Riders gains flying until end of turn.

Protection from red

Elemental creatures you control get +1/+1.

When Master of Waves enters, 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.

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, tap target creature an opponent controls. It loses all abilities until end of turn.

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

Whenever you cast a Merfolk spell, you may tap or untap target permanent.

{T}: Add {C}.

{3}, {T}, Sacrifice a creature: You gain life equal to the sacrificed creature's toughness.

Mist-Cloaked Herald can't be blocked.

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

{T}: Add {C}.

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

{T}: Add {C}.

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

Bestow {4}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)

Enchanted creature gets +2/+3.

Oran-Rief, the Vastwood enters tapped.

{T}: Add {G}.

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

Path of Ancestry enters 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.)

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.

{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.

{1}{U}, {T}: Return target creature with a counter on it to its owner's hand.

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

You have no maximum hand size.

{T}: Add {C}.

River Sneak can't be blocked.

Whenever another Merfolk enters the battlefield under your control, River Sneak gets +1/+1 until end of turn.

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Each other Wizard creature you control enters the battlefield with an additional +1/+1 counter on it.

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

Whenever Saltwater Stalwart deals damage to an opponent, target player draws a card.

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.

When you control no Islands, sacrifice Seasinger.

You may choose not to untap Seasinger during your untap step.

{T}: Gain control of target creature whose controller controls an Island for as long as you control Seasinger and Seasinger remains tapped.

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.

{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.

{T}: Target creature gets -X/-0 until end of turn, where X is the number of Merfolk and/or Faeries you control.

{1}{U}, {T}: You may tap or untap target creature.

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.

{T}: Add {C}.

{T}, Sacrifice Strip Mine: Destroy target land.

Tap another untapped Rogue you control: Sure-Footed Infiltrator can't be blocked this turn.

Whenever Sure-Footed Infiltrator deals combat damage to a player, draw a card.

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.)

Landfall -- Whenever a land enters the battlefield under your control, you gain 1 life and draw a card.

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

Temple of Mystery enters tapped.

When Temple of Mystery enters, scry 1.

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

When Thassa's Oracle enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

{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.)

When Tidal Courier enters the battlefield, reveal the top four cards of your library. Put all Merfolk cards revealed this way into your hand and the rest on the bottom of your library in any order.

{3}{U}: Tidal Courier gains flying until end of turn.

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

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

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.

Triton Shorestalker can't be blocked.

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

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.

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

{T}: Add {C}.

{T}, Sacrifice Wasteland: Destroy target nonbasic land.

{T}: Add {C}.

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

{T}: Add {C}.

{G}, {T}: Regenerate target creature.