At the beginning of your upkeep, you may put a charge counter on Aether Vial. {T}: You may put a creature card with mana value equal to the number of charge counters on Aether Vial from your hand onto the battlefield.

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn. Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

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

Astral Cornucopia enters the battlefield with X charge counters on it. {T}: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.

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.

Imprint — When Extraplanar Lens enters the battlefield, you may exile target land you control. Whenever a land with the same name as the exiled card is tapped for mana, its controller adds one mana of any type that land produced.

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.) Equip {0}

{T}: Add one mana of any color among legendary creatures and planeswalkers you control.

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 Obelisk of Urd enters the battlefield, choose a creature type. Creatures you control of the chosen type get +2/+2.

As Pillar of Origins enters the battlefield, choose a creature type. {T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

As Prism Ring enters the battlefield, choose a color. Whenever you cast a spell of the chosen color, you gain 1 life.

{1}: Look at the top three cards of your library, then put them back in any order. {T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Equipped creature gets +1/-1. Whenever equipped creature dies, draw two cards. Equip {1}

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

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.) Equip {1}

Flash (You may cast this spell any time you could cast an instant.) Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Brineborn Cutthroat.

Whenever Cleric of Chill Depths blocks a creature, that creature doesn't untap during its controller's next untap step.

Whenever an opponent shuffles their library, you may put a +1/+1 counter on Cosi's Trickster.

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

{U}, {T}: Each player reveals the top card of their library. You may put the revealed cards into their owners' graveyards. If you don't, each player draws a card.

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.

{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.

Level up {2} ({2}: Put a level counter on this. Level up only as a sorcery.) LEVEL 1-4 0/6 LEVEL 5+ 6/6 Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

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.

Creatures you control with +1/+1 counters on them can't be blocked.

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.

Leech Bonder enters the battlefield with two -1/-1 counters on it. {U}, {Q}: Move a counter from target creature onto a second target creature. ({Q} is the untap symbol.)

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

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

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

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 Whenever Merfolk Windrobber deals combat damage to a player, that player mills a card. (They put the top card of their library into their graveyard.) Sacrifice Merfolk Windrobber: 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.

As Metallic Mimic enters the battlefield, choose a creature type. Metallic Mimic is the chosen type in addition to its other types. Each other creature you control of the chosen type enters the battlefield with an additional +1/+1 counter on it.

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.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) {T}: Add {C}.

Whenever Riptide Pilferer deals combat damage to a player, that player discards a card. Morph {U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

River Sneak can't be blocked. Whenever another Merfolk enters the battlefield under your control, River Sneak gets +1/+1 until end of turn.

Shaper Apprentice has flying as long as you control another Merfolk.

{T}: Add {U}.

{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.

{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.

Svyelun of Sea and Sky 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}.)

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.

{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.

As True-Name Nemesis enters the battlefield, choose a player. True-Name Nemesis has protection from the chosen player.

When Urza, Lord High Artificer enters the battlefield, create a 0/0 colorless Construct artifact creature token with "This creature gets +1/+1 for each artifact you control." Tap an untapped artifact you control: Add {U}. {5}: Shuffle your library, then exile the top card. Until end of turn, you may play that card without paying its mana cost.

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

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

Flash (You may cast this spell any time you could cast an instant.) Enchant creature Enchanted creature gets +1/+1. Totem armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

As Kindred Discovery enters the battlefield, choose a creature type. Whenever a creature you control of the chosen type enters the battlefield or attacks, draw a card.

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

As an additional cost to cast this spell, sacrifice a blue permanent. Counter target spell.

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

Return target nonland permanent you don't control to its owner's hand. Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Counter target creature spell. Put a +1/+1 counter on up to one target creature you control.

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

Castle Vantress enters the battlefield tapped unless you control an Island. {T}: Add {U}. {2}{U}{U}, {T}: Scry 2.

As Cavern of Souls enters the battlefield, 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, and that spell can't be countered.

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

({T}: Add {U}.)

{T}: Add {U}. {U}, {T}: Untap target legendary permanent.

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

{T}: Add {C}. {2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.