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

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

You have no maximum hand size. {T}: Add one mana of any color.

{T}: Add {C}. {T}: Roll the planar die. Activate only as a sorcery.

Equipped creature gets +1/+1. Whenever equipped creature deals combat damage to a player, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.") Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

{T}: Add one mana of any color. {2}, {T}: Exile target card from a graveyard.

{T}: Add one mana of any color. {4}, {T}: Look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, you may put it on the bottom of your library.

{T}: Add one mana of any color.

{T}: Add {C}. You gain 1 life.

Equipped creature gets +1/+0. Whenever equipped creature deals combat damage to a player, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.") Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

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

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

Star Compass enters the battlefield tapped. {T}: Add one mana of any color that a basic land you control could produce.

{U}: Deeptread Merrow gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.)

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

{5}{U}{U}: Frilled Sea Serpent can't be blocked this turn.

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.

Islandwalk (This creature can't be blocked as long as defending player controls an Island.) Harbor Serpent can't attack unless there are five or more Islands on the battlefield.

Kukemssa Serpent can't attack unless defending player controls an Island. {U}, Sacrifice an Island: Target land an opponent controls becomes an Island until end of turn. When you control no Islands, sacrifice Kukemssa Serpent.

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

Islandwalk (This creature can't be blocked as long as defending player controls an Island.) Whenever Merfolk Spy deals combat damage to a player, that player reveals a card at random from their hand.

When Octoprophet enters the battlefield, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

When Prosperous Pirates enters the battlefield, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

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

River Serpent can't attack unless there are five or more cards in your graveyard. Cycling {U} ({U}, Discard this card: Draw a card.)

When Sailor of Means enters the battlefield, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Cycling {2} ({2}, Discard this card: Draw a card.)

Scrapdiver Serpent can't be blocked as long as defending player controls an artifact.

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

Serpent of the Endless Sea's power and toughness are each equal to the number of Islands you control. Serpent of the Endless Sea can't attack unless defending player controls an Island.

{T}: Add {U}.

Defender Metalcraft — As long as you control three or more artifacts, Spire Serpent gets +2/+2 and can attack as though it didn't have defender.

Steelclad Serpent can't attack unless you control another artifact.

{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.

Hexproof (This creature can't be the target of spells or abilities your opponents control.) Cycling {U} ({U}, Discard this card: Draw a card.)

Whenever Tidal Terror attacks, you may tap two other untapped creatures you control. If you do, Tidal Terror can't be blocked this turn. Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

{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.

Triton Shorestalker can't be blocked.

Enchant land (Target a land as you cast this. This card enters the battlefield attached to that land.) Enchanted land is an Island.

Counter target spell.

Counter target spell.

Scry 2, then draw a card.

Counter target spell with mana value 4 or greater.

Counter target spell that targets a creature.

Target land becomes the basic land type of your choice until end of turn. Draw a card at the beginning of the next turn's upkeep.

Replicate {U} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.) Counter target spell unless its controller pays {2}.

Counter target spell unless its controller pays {2}. Cycling {2} ({2}, Discard this card: Draw a card.)

Counter target noncreature spell.

Scry 1. Draw a card.

Target land becomes the basic land type of your choice until end of turn. Draw a card.

Counter target spell unless its controller pays {1} for each blue permanent you control.

Metalcraft — This spell costs {1} less to cast if you control three or more artifacts. Counter target spell.

{T}: Add {C}. Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

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

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 {U}.)

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

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.

Draw two cards. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

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.)

Deep-Sea Terror can't attack unless there are seven or more cards in your graveyard.

Defender Megamorph {6}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

Floodtide Serpent can't attack unless you return an enchantment you control to its owner's hand. (This cost is paid as attackers are declared.)

Defender When Gleaming Barrier dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Islandwalk (This creature can't be blocked as long as defending player controls an Island.) When Inkfathom Divers enters the battlefield, look at the top four cards of your library, then put them back in any order.

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

Whenever Marching Duodrone attacks, each player creates a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Flying {2}, Return a land you control to its owner's hand: Target land becomes the basic land type of your choice until end of turn.

Scry 2, then draw a card. Flashback {4}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Defender Landfall — Whenever a land enters the battlefield under your control, Shoal Serpent loses defender until end of turn.