Return all attacking creatures to their owner's hand.

For each attacking creature, its owner puts it on the top or bottom of their library.

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Enchant creature

Enchanted creature can't be blocked.

Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

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

Choose one --

• Counter target spell.

• Target player draws two cards.

• Gain control of target nonland permanent with mana value 1 or less.

When Augur of Bolas enters the battlefield, look at the top three cards of your library. You may reveal an instant or sorcery card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

{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.

Changeling (This card is every creature type.)

As Bloodline Pretender enters the battlefield, choose a creature type.

Whenever another creature of the chosen type enters the battlefield under your control, put a +1/+1 counter on Bloodline Pretender.

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

Flash (You may cast this spell any time you could cast an instant.)

Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Brineborn Cutthroat.

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

{T}: Add {U}.

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

Draw two cards. Then discard a card unless you attacked this turn.

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

Sacrifice Commander's Sphere: Draw a card.

Each player chooses a nonland permanent they control. Return all nonland permanents not chosen this way to their owners' hands. Then you draw a card for each opponent who has more cards in their hand than you.

Coral Atoll enters the battlefield tapped.

When Coral Atoll enters the battlefield, sacrifice it unless you return an untapped Island you control to its owner's hand.

{T}: Add {C}{U}.

Counter target spell.

This spell has flash as long as you control a Merfolk.

Return target creature to its owner's hand.

Draw a card.

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Counter target spell. If the spell is countered this way, exile it with three time counters on it instead of putting it into its owner's graveyard. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, remove a time counter from that card. When the last is removed, the player plays it without paying its mana cost. If it's a creature, it has haste.)

Desert of the Mindful enters the battlefield tapped.

{T}: Add {U}.

Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)

Untap all nonland permanents you control.

Draw a card for each Island you control, then discard two cards.

Gray Harbor Merfolk can't be blocked.

Gray Harbor Merfolk gets +2/+0 as long as you control a commander that's a creature or planeswalker.

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}.

Equipped creature gets +3/+1.

Whenever equipped creature dies, you may reveal cards from the top of your library until you reveal a creature card that shares a creature type with it. Put that card into your hand and the rest on the bottom of your library in a random order.

Equip {1}

As Heraldic Banner enters the battlefield, choose a color.

Creatures you control of the chosen color get +1/+0.

{T}: Add one mana of the chosen color.

Hidden Cataract enters the battlefield tapped.

{T}: Add {U}.

{4}{U}, {T}, Sacrifice Hidden Cataract: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Enchant creature, land, or planeswalker

Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.

({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 {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

Blue creature spells you cast cost {1} less to cast.

Whenever you cast a creature spell, target creature an opponent controls doesn't untap during its controller's next untap step.

All lands are Islands in addition to their other types.

Other Homarids, Camarids, Cephalids, Nautilids, and Merfolk you control get +1/+1.

Lonely Sandbar enters the battlefield tapped.

{T}: Add {U}.

Cycling {U} ({U}, Discard this card: Draw a card.)

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.

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Memorial to Genius enters the battlefield tapped.

{T}: Add {U}.

{4}{U}, {T}, Sacrifice Memorial to Genius: Draw two cards.

{T}: Draw a card, then discard a card.

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.

Flying

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

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.

{T}: Add {U}.

{2}{U}: Put an hour counter on Midnight Clock.

At the beginning of each upkeep, put an hour counter on Midnight Clock.

When the twelfth hour counter is put on Midnight Clock, shuffle your hand and graveyard into your library, then draw seven cards. Exile Midnight Clock.

Whenever you attack with two or more creatures, draw a card.

{T}: Add {C}.

{1}, {T}, Sacrifice Mind Stone: Draw a card.

Mist-Cloaked Herald can't be blocked.

Sacrifice Mistcaller: Until end of turn, if a nontoken creature would enter the battlefield and it wasn't cast, exile it instead.

Myriad Landscape enters the battlefield tapped.

{T}: Add {C}.

{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

({T}: Add {U}.)

Mystic Sanctuary enters the battlefield tapped unless you control three or more other Islands.

When Mystic Sanctuary enters the battlefield untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

Each opponent can't draw more than one card each turn.

-2: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Counter target noncreature spell.

Nyx Lotus enters the battlefield tapped.

{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.

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.

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.)

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.

Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

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}.

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

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

{1}, {T}: Tap target land.

River Sneak can't be blocked.

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

Return all nonland permanents target player controls to their owner's hand.

When Riverwise Augur enters the battlefield, draw three cards, then put two cards from your hand on top of your library in any order.

{T}: Add {C}.

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

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

When Salvager of Secrets enters the battlefield, return target instant or sorcery card from your graveyard to your hand.

Counter target spell.

Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

When Scourge of Fleets enters the battlefield, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

Flash

When Sentinel of the Pearl Trident enters the battlefield, you may exile target historic permanent you control. If you do, return that card to the battlefield under its owner's control at the beginning of the next end step. (Artifacts, legendaries, and Sagas are historic.)

Sky Diamond enters the battlefield tapped.

{T}: Add {U}.

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

When Slinn Voda, the Rising Deep enters the battlefield, if it was kicked, return all creatures to their owners' hands except for Merfolk, Krakens, Leviathans, Octopuses, and Serpents.

{T}: Add {C}{C}.

Search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

Foretell {1}{U}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

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

Equipped creature gets +1/+1 for each other creature you control that shares a creature type with it.

Equip {2}

Exile target creature and put two time counters on it. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, they remove a time counter. When the last is removed, they play it without paying its mana cost. If it's a creature, it has haste.)

Svyelun of Sea and Sky has indestructible as long as you control at least two other Merfolk.

Whenever Svyelun attacks, draw a card.

Other Merfolk you control have ward {1}. (Whenever another Merfolk you control becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)

Equip {1}

Equipped creature gets +1/+1.

Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Equip {2}

Whenever you cast an instant or sorcery spell, create a 2/2 blue Drake creature token with flying.

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.

When Thassa's Oracle enters the battlefield, 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.)

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.

You have no maximum hand size.

{T}: Add {C}.

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

When Tide Shaper enters the battlefield, if it was kicked, target land becomes an Island for as long as Tide Shaper remains on the battlefield.

Tide Shaper gets +1/+1 as long as an opponent controls an Island.

Tolaria West enters the battlefield tapped.

{T}: Add {U}.

Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with mana value 0, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Heroic -- Whenever you cast a spell that targets Triton Fortune Hunter, draw a card.

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.

{T}: Add {C}.

{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Cleave {1}{U}{U} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)

Counter target spell [that wasn't cast from its owner's hand].

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

This spell costs {1} less to cast if you control a Wizard.

Counter target spell.

Flying

As long as Wonder is in your graveyard and you control an Island, creatures you control have flying.