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

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.

{T}: Add one mana of any color in your commander's color identity. Sacrifice Commander's Sphere: Draw a card.

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.

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.

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

Sky Diamond enters the battlefield tapped. {T}: Add {U}.

Sacrifice Cursecatcher: Counter target instant or sorcery spell unless its controller pays {1}.

You may look at the top card of your library any time. You may cast Merfolk spells from the top of your library. Whenever you cast a Merfolk spell, you may pay {1}. If you do, create a 1/1 blue Merfolk creature token.

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.

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.

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.

Whenever Library Larcenist attacks, draw a card.

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}: Draw a card, then discard a card.

When Merfolk Pupil enters the battlefield, draw a card, then discard a card. {1}{U}, Exile Merfolk Pupil from your graveyard: 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.

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.

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.

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.

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

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.

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.

Islandwalk (This creature can't be blocked as long as defending player controls an Island.) All lands are Islands in addition to their other types. Creatures without flying or islandwalk can't attack.

{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.

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.

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.

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

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.

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

Triton Shorestalker can't be blocked.

Flash Other Merfolk you control get +1/+1. Sacrifice a Merfolk: Counter target noncreature spell unless its controller pays {1}.

When Aquatic Incursion enters the battlefield, create two 1/1 blue Merfolk creature tokens with hexproof. (They can't be the targets of spells or abilities your opponents control.) {3}{U}: Target Merfolk can't be blocked this turn.

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.)

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

Whenever a creature you control deals combat damage to a player, you may draw a card. Cycling {2} ({2}, Discard this card: Draw a card.)

As Reflections of Littjara enters the battlefield, choose a creature type. Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

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.

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

Counter target spell.

Choose one — • Counter target artifact or enchantment spell. If a spell is countered this way, exile it instead of putting it into its owner's graveyard. • Counter target activated or triggered ability.

Return all noncreature, nonland permanents to their owners' hands.

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

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Counter target noncreature spell.

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

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.)

({T}: Add {U}.)

Lonely Sandbar enters the battlefield tapped. {T}: Add {U}. Cycling {U} ({U}, Discard this card: Draw a card.)

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.

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.)

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.

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.

This spell has flash as long as you control a Merfolk. Return target creature to its owner's hand. Draw a card.

Choose a creature type. Draw a card for each permanent you control of that type.

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.)