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

Create a token that's a copy of target creature you control. Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Counter target sorcery spell.

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.)

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.)

When this artifact enters, each opponent sacrifices three creatures of their choice. At the beginning of your upkeep, put target creature card from a graveyard onto the battlefield under your control. It's a Phyrexian in addition to its other types.

{T}: Add {C}. {2}, {T}, Sacrifice this land: Return target artifact card from your graveyard to your hand.

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

({T}: Add {G}.)

{T}: Add {C}. {2}, {T}: Each player draws a card, then discards a card.

({T}: Add {G} or {U}.) This land enters tapped. When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

This land enters tapped unless you control a Forest or an Island. {T}: Add {G} or {U}.

({T}: Add {U}.)

This land enters tapped. {T}: Add {U}. {2}{G}{G}{U}, {T}, Sacrifice this land: Create a token that's a copy of target creature you control, except it enters with an additional +1/+1 counter on it. Activate only as a sorcery.

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

{T}: Add {C}. {2}, {T}: Each player draws a card.

This land enters tapped. {T}: Add {C}. {2}{C}, {T}, Sacrifice this land: Copy target instant or sorcery spell you control. You may choose new targets for the copy. {4}{C}, {T}, Sacrifice this land: Create a token that's a copy of target creature you control.

{T}: Add {C}. {1}: This land becomes a 2/2 creature with all creature types until end of turn. It's still a land.

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.)

This land enters tapped. {T}: Add {G} or {U}. {4}, {T}: Scry 1.

This land enters tapped unless you have two or more opponents. {T}: Add {G} or {U}.

Rivendell enters tapped unless you control a legendary creature. {T}: Add {U}. {1}{U}, {T}: Scry 2. Activate only if you control a legendary creature.

As this land enters, 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 or activate an ability of a creature source of the chosen type.

This land enters tapped. {T}: Add {U}. {T}, Sacrifice this land: Add {U}{U}.

This land enters tapped. When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.) {T}: Add {G} or {U}.

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

As this land enters, 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.

As this land enters, you may reveal a Forest or Island card from your hand. If you don't, this land enters tapped. {T}: Add {G} or {U}.

{T}, Pay 1 life: Add {G} or {U}. {1}, {T}, Sacrifice this land: Draw a card.

Changeling (This card is every creature type.) {T}: Target creature gains all creature types until end of turn. {T}: Target creature loses all creature types until end of turn.

{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 this creature, draw a card, then discard a card.

At the beginning of combat on your turn, this creature explores. Then you may have it become a copy of another creature you control until end of turn. (To have this creature explore, reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

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.

{T}: Untap another target permanent you control. {T}, Collect evidence 3: Tap target creature you don't control. (To collect evidence 3, exile cards with total mana value 3 or greater from your graveyard.)

This creature can't be blocked. This creature gets +2/+0 as long as you control a commander that's a creature or planeswalker.

When this creature enters, it explores X times. (To have it explore, reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on that creature, then put the card back or put it into your graveyard.)

{T}: Untap another target permanent.

Reach Modified creatures you control have trample. (Equipment, Auras you control, and counters are modifications.) Whenever a modified creature you control deals combat damage to a player, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

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.

Changeling (This card is every creature type.) When this creature enters, you may exile a creature card from your graveyard. If you do, exile target artifact or enchantment an opponent controls.

Whenever a creature you control explores, this creature gets +1/+0 until end of turn and can't be blocked this turn.

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.

Flying Other Merfolk you control get +1/+0 and have flying. Encore {5}{U}{U} ({5}{U}{U}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

This creature can't be blocked.

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

Changeling (This card is every creature type.) Tap an untapped creature you control: This creature gains flying until end of turn.

Whenever a creature you control explores a land card, you may put a land card from your hand onto the battlefield tapped. Whenever a creature you control explores a nonland card, put a +1/+1 counter on Nicanzil.

Ward {2} As this creature enters, choose a creature type. This creature is the chosen type in addition to its other types. If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

{T}, Sacrifice this creature: Return target artifact card from your graveyard to your hand.

When this creature enters, return target instant or sorcery card from your graveyard to your hand.

Whenever this creature becomes blocked, you may draw three cards.

If an opponent controls a Mountain and you control an Island, you may cast this spell without paying its mana cost. Flying

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

Changeling (This card is every creature type.) {2}{U}: Target Shapeshifter becomes a copy of target creature until your next turn.

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.

Flash When this creature enters, put a shield counter on another target creature you control. (If it would be dealt damage or destroyed, remove a shield counter from it instead.) You may cast Merfolk spells as though they had flash.

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.

Svyelun 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}.)

Kicker {X}. X can't be 0. (You may pay an additional {X} as you cast this spell.) Flying When this creature enters, if it was kicked, gain control of target artifact with mana value X or less. If that artifact is an Equipment, attach it to this creature.

When this creature enters, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.") If a creature you control would explore, instead it explores, then it explores again.

This spell can't be countered. Indestructible Toski attacks each combat if able. Whenever a creature you control deals combat damage to a player, draw a card.

This creature can't be blocked.

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

Champion a Merfolk (When this enters, sacrifice it unless you exile another Merfolk you control. When this leaves the battlefield, that card returns to the battlefield.) Whenever this creature deals combat damage to a player, you may sacrifice a Merfolk. If you do, take an extra turn after this one.

Descend 8 — When you cast this spell, if there are eight or more permanent cards in your graveyard, copy this spell twice. You may choose new targets for the copies. Return target permanent card from your graveyard to your hand. Exile Bygone Marvels.

For each of X target permanents, create X tokens that are copies of that permanent.

Target creature you control explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.) You may play an additional land this turn.

Destroy target artifact or enchantment. Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)

Take an extra turn after this one. Skip the untap step of that turn.

Whenever a creature you control with a +1/+1 counter on it deals combat damage to a player, you may draw a card.

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.

Whenever one or more nontoken Merfolk you control become tapped, create a 1/1 blue Merfolk creature token with hexproof.

Enchant creature you control At the beginning of your upkeep, create a token that's a copy of enchanted creature, except the token is 1/1. When enchanted creature dies, if that creature was a Horror, return this card to its owner's hand.

You may play an additional land on each of your turns.

Enchant creature Whenever enchanted creature deals combat damage to a player, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Enchant creature Enchanted creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)