{T}: Add {W} or {U}. {W}{U}, {T}, Sacrifice Azorius Cluestone: Draw a card.

{1}, {T}: Add {W}{U}.

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.

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

As Door of Destinies enters the battlefield, choose a creature type. Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies. Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

At the beginning of each player's upkeep, that player puts a flood counter on target non-Island land they control of their choice. That land is an Island for as long as it has a flood counter on it. At the beginning of each end step, if all lands on the battlefield are Islands, remove all flood counters from them.

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

As Adaptive Automaton enters the battlefield, choose a creature type. Adaptive Automaton is the chosen type in addition to its other types. Other creatures you control of the chosen type get +1/+1.

Tap an untapped Wizard you control: Draw a card.

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.

Defender (This creature can't attack.) Flying Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Tap an untapped Merfolk you control: Target player mills a card.

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

Level up {1}{U} ({1}{U}: Put a level counter on this. Level up only as a sorcery.) LEVEL 1-2 0/1 {T}: Draw a card, then discard a card. LEVEL 3+ 0/1 {T}: Draw a card.

Whenever Fallowsage becomes tapped, you may draw a card.

{W}, {T}: Harpoon Sniper deals X damage to target attacking or blocking creature, where X is the number of Merfolk you control.

Whenever a Merfolk you control becomes tapped, you may gain 1 life.

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

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.

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

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

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.

Changeling (This card is every creature type.) {X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

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

{T}: Gain control of target creature for as long as that creature is enchanted.

{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.

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

{3}, {T}: Search your library for a Merfolk permanent card, put it onto the battlefield, then shuffle.

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.

{1}{U}, Tap two untapped Wizards you control: Copy target instant or sorcery spell. You may choose new targets for the copy.

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.

Whenever Stonybrook Schoolmaster becomes tapped, you may create a 1/1 blue Merfolk Wizard creature token.

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.

Vigilance Whenever Sun Titan enters the battlefield or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Whenever Surgespanner becomes tapped, you may pay {1}{U}. If you do, return target permanent to its owner's hand.

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.

Indestructible As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.) At the beginning of your upkeep, scry 1. {1}{U}: Target creature you control can't be blocked this turn.

Whenever Veteran of the Depths becomes tapped, you may put a +1/+1 counter on it.

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

Enchant creature At the beginning of your upkeep, you may look at the top five cards of your library. If you do, you may put a creature card that shares a creature type with enchanted creature from among them onto the battlefield, then you put the rest of those cards on the bottom of your library in any order.

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

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

Counter target instant or sorcery spell. Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Counter target spell. Its controller can't cast spells this turn.

You gain X life and draw X cards.

Azorius Chancery enters the battlefield tapped. When Azorius Chancery enters the battlefield, return a land you control to its owner's hand. {T}: Add {W}{U}.

Azorius Guildgate enters the battlefield tapped. {T}: Add {W} or {U}.

Celestial Colonnade enters the battlefield tapped. {T}: Add {W} or {U}. {3}{W}{U}: Until end of turn, Celestial Colonnade becomes a 4/4 white and blue Elemental creature with flying and vigilance. It's still a land.

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

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Flood Plain enters the battlefield tapped. {T}, Sacrifice Flood Plain: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Glacial Fortress enters the battlefield tapped unless you control a Plains or an Island. {T}: Add {W} or {U}.

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}.

({T}: Add {W} or {U}.) As Hallowed Fountain enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

({T}: Add {U}.)

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

{T}: Add {C}. {W/U}, {T}: Add {W}{W}, {W}{U}, or {U}{U}.

{T}: Add {C}. {T}: Add {W}. Activate only if you control an Island. {T}: Add {U}. Activate only if you control a Plains.

({T}: Add {W}.)

As Port Town enters the battlefield, you may reveal a Plains or Island card from your hand. If you don't, Port Town enters the battlefield tapped. {T}: Add {W} or {U}.

{T}: Add {C}. {4}{W}{U}, {T}: Prevent all damage a source of your choice would deal this turn.

({T}: Add {W} or {U}.) Prairie Stream enters the battlefield tapped unless you control two or more basic lands.

You have no maximum hand size. {T}: Add {C}.

{T}: Add {C}. {1}{U}, {T}: Return target Wizard you control to its owner's hand.

Secluded Steppe enters the battlefield tapped. {T}: Add {W}. Cycling {W} ({W}, Discard this card: Draw a card.)

Sejiri Refuge enters the battlefield tapped. When Sejiri Refuge enters the battlefield, you gain 1 life. {T}: Add {W} or {U}.

Temple of Enlightenment enters the battlefield tapped. When Temple of Enlightenment enters the battlefield, scry 1. {T}: Add {W} or {U}.

Tranquil Cove enters the battlefield tapped. When Tranquil Cove enters the battlefield, you gain 1 life. {T}: Add {W} or {U}.

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.

Create two 1/1 blue Merfolk Wizard creature tokens. Tap four untapped Merfolk you control: Return Summon the School from your graveyard to your hand.