Dark Depths enters with ten ice counters on it. {3}: Remove an ice counter from Dark Depths. When Dark Depths has no ice counters on it, sacrifice it. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

({T}: Add {U}.)

This land enters tapped. {T}: Add {U}. Cycling {U} ({U}, Discard this card: Draw a card.)

This land 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.)

Equipped creature gets +1/+1 for each land you control. Equip legendary creature {3} Equip {7}

As this artifact enters, choose a color. Creatures you control of the chosen color get +1/+1. Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

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.)

{2}, {T}: Draw a card. Activate only if you control three or more lands with the same name.

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}

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) As this artifact enters, choose a creature type. Creatures you control of the chosen type get +2/+2.

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

{T}: Add one mana of any color. {T}: Add three mana of any one color. Activate only if you control three or more lands with the same name.

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.) Equipped creature gets +1/+1. Whenever equipped creature deals combat damage to a player, that player loses half their life, rounded up. Equip {3}

This artifact enters tapped. {T}: Add {U}.

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

As this artifact enters, choose a creature type. Creature spells of the chosen type cost {2} less to cast.

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 three cards.

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

Callaphe's power is equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.) Creatures and enchantments you control have "Spells your opponents cast that target this permanent cost {1} more to cast."

Flying As an additional cost to cast blue permanent spells, you may pay 2 life. Those spells cost {U} less to cast if you paid life this way. This effect reduces only the amount of blue mana you pay. Whenever you cast a blue permanent spell, draw a card.

Whenever this creature becomes tapped, you may draw a card.

Nonbasic lands are Islands.

You may cast this card 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 this creature enters, you may return target tapped creature an opponent controls to its owner's hand.

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

When Kiora enters, draw two cards, then discard two cards. Threshold — Whenever Kiora attacks, if there are seven or more cards in your graveyard, you may create Scion of the Deep, a legendary 8/8 blue Octopus creature token.

Whenever this creature 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.)

Protection from red Elemental creatures you control get +1/+1. When this creature 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.)

{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.

Flying When this creature enters, 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.

Flying Whenever this creature deals combat damage to a player, that player mills a card. (They put the top card of their library into their graveyard.) Sacrifice this creature: Draw a card. Activate only if an opponent has eight or more cards in their graveyard.

Other Merfolk creatures you control get +1/+1. Whenever you cast a Merfolk spell, you may tap or untap target permanent.

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

Flying When this creature enters, draw two cards. Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

{T}: This creature deals 1 damage to any target.

You may have Sakashima enter as a copy of another creature you control, except it has Sakashima's other abilities. The "legend rule" doesn't apply to permanents you control. Partner (You can have two commanders if both have partner.)

Whenever this creature deals combat damage to a player, draw a card.

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

Flash When this creature enters, 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.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) When this creature enters, return target instant or sorcery card from your graveyard to your hand.

As an additional cost to cast this spell, reveal a Merfolk card from your hand or pay {3}. When this creature enters, draw a card.

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

{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.

Tap another untapped Rogue you control: This creature can't be blocked this turn. Whenever this creature deals combat damage to a player, draw a card.

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.) As long as Tandem Lookout is paired with another creature, each of those creatures has "Whenever this creature deals damage to an opponent, draw a card."

When this creature enters, tap all creatures target opponent controls.

When this creature enters, 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}: This creature gains flying until end of turn.

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

Kicker {1} (You may pay an additional {1} as you cast this spell.) When this creature enters, if it was kicked, target land becomes an Island for as long as this creature remains on the battlefield. This creature gets +1/+1 as long as an opponent controls an Island.

When this creature enters, tap target red or green creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control this creature.

This creature can't be blocked.

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.

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

When this creature enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Commander creatures you own have "Whenever one or more nontoken creatures you control deal combat damage to a player, you create a 1/1 blue Faerie Dragon creature token with flying."

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

As this enchantment enters, 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.)

You may exile two blue cards from your hand rather than pay this spell's mana cost. Gain control of target noncreature spell. You may choose new targets for it. (If that spell is an artifact, enchantment, or planeswalker, the permanent enters under your control.)

Counter target spell that targets a creature. Draw a card.

Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.

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