Command Tower

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

Reliquary Tower

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

Circle of Protection: Blue

{1}: The next time a blue source of your choice would deal damage to you this turn, prevent that damage.

Celestial Mantle

Enchant creature
Enchanted creature gets +3/+3.
Whenever enchanted creature deals combat damage to a player, double its controller's life total.

Banishing Light

When Banishing Light enters the battlefield, exile target nonland permanent an opponent controls until Banishing Light leaves the battlefield.

Spellbook

Heartbeat of Spring

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Circle of Protection: Red

{1}: The next time a red source of your choice would deal damage to you this turn, prevent that damage.

Nykthos Paragon

Whenever you gain life, you may put that many +1/+1 counters on each creature you control. Do this only once each turn.

Vodalian Mystic

{T}: Target instant or sorcery spell becomes the color of your choice.

Judge of Currents

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

Archetype of Imagination

Creatures you control have flying.
Creatures your opponents control lose flying and can't have or gain flying.

Gray Harbor Merfolk

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.

Sol Ring

Arcane Signet

Frozen Aether

Artifacts, creatures, and lands your opponents control enter the battlefield tapped.

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Irrigated Farmland

({T}: Add {W} or {U}.)
Irrigated Farmland enters the battlefield tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Callaphe, Beloved of the Sea

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."

Colossification

Enchant creature
When Colossification enters the battlefield, tap enchanted creature.
Enchanted creature gets +20/+20.

Estrid's Invocation

You may have Estrid's Invocation enter the battlefield as a copy of an enchantment you control, except it has "At the beginning of your upkeep, you may exile this enchantment. If you do, return it to the battlefield under its owner's control."

Curse of Verbosity

Enchant player
Whenever enchanted player is attacked, you draw a card. Each opponent attacking that player does the same.

Bident of Thassa

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.

Blighted Woodland

{T}: Add {C}.
{3}{G}, {T}, Sacrifice Blighted Woodland: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Stonybrook Schoolmaster

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

Empress Galina

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

Mirrormade

You may have Mirrormade enter the battlefield as a copy of any artifact or enchantment on the battlefield.

Angelic Destiny

Enchant creature
Enchanted creature gets +4/+4, has flying and first strike, and is an Angel in addition to its other types.
When enchanted creature dies, return Angelic Destiny to its owner's hand.

Gaea's Skyfolk

Tuvasa the Sunlit

Tuvasa the Sunlit gets +1/+1 for each enchantment you control.
Whenever you cast your first enchantment spell each turn, draw a card.

Destiny Spinner

Creature and enchantment spells you control can't be countered.
{3}{G}: Target land you control becomes an X/X Elemental creature with trample and haste until end of turn, where X is the number of enchantments you control. It's still a land.

Beastmaster Ascension

Whenever a creature you control attacks, you may put a quest counter on Beastmaster Ascension.
As long as Beastmaster Ascension has seven or more quest counters on it, creatures you control get +5/+5.

Towering-Wave Mystic

Whenever Towering-Wave Mystic deals damage, target player mills that many cards.

All That Glitters

Enchant creature
Enchanted creature gets +1/+1 for each artifact and/or enchantment you control.

Celestial Archon

Bestow {5}{W}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying, first strike
Enchanted creature gets +4/+4 and has flying and first strike.

Enchantress's Presence

Whenever you cast an enchantment spell, draw a card.

Merrow Harbinger

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.

Commander's Sphere

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

Triton Shorestalker

Merfolk Mistbinder

Arbiter of the Ideal

Flying
Inspired — Whenever Arbiter of the Ideal becomes untapped, reveal the top card of your library. If it's an artifact, creature, or land card, you may put it onto the battlefield with a manifestation counter on it. That permanent is an enchantment in addition to its other types.

Harvestguard Alseids

Constellation — Whenever Harvestguard Alseids or another enchantment enters the battlefield under your control, prevent all damage that would be dealt to target creature this turn.

Fallowsage

Whenever Fallowsage becomes tapped, you may draw a card.

Circle of Protection: White

{1}: The next time a white source of your choice would deal damage to you this turn, prevent that damage.

Golden-Tail Disciple

Aegis of the Gods

You have hexproof. (You can't be the target of spells or abilities your opponents control.)

Sygg, River Guide

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
{1}{W}: Target Merfolk you control gains protection from the color of your choice until end of turn.

Estrid, the Masked

+2: Untap each enchanted permanent you control.
−1: Create a white Aura enchantment token named Mask attached to another target permanent. The token has enchant permanent and umbra armor.
−7: Mill seven cards. Return all non-Aura enchantment cards from your graveyard to the battlefield, then do the same for Aura cards.
Estrid, the Masked can be your commander.

Cold-Eyed Selkie

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Cold-Eyed Selkie deals combat damage to a player, you may draw that many cards.

Plains

Tatyova, Benthic Druid

Landfall — Whenever a land enters the battlefield under your control, you gain 1 life and draw a card.

Scroll Thief

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

Detention Sphere

When Detention Sphere enters the battlefield, you may exile target nonland permanent not named Detention Sphere and all other permanents with the same name as that permanent.
When Detention Sphere leaves the battlefield, return the exiled cards to the battlefield under their owner's control.

Master of the Pearl Trident

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

Brilliant Restoration

Return all artifact and enchantment cards from your graveyard to the battlefield.

Auramancer's Guise

Enchant creature
Enchanted creature gets +2/+2 for each Aura attached to it and has vigilance.

Brushland

{T}: Add {C}.
{T}: Add {G} or {W}. Brushland deals 1 damage to you.

Propaganda

Vodalian Mage

{U}, {T}: Counter target spell unless its controller pays {1}.

Ashiok's Erasure

Flash
When Ashiok's Erasure enters the battlefield, exile target spell.
Your opponents can't cast spells with the same name as the exiled card.
When Ashiok's Erasure leaves the battlefield, return the exiled card to its owner's hand.

Aura of Silence

Artifact and enchantment spells your opponents cast cost {2} more to cast.
Sacrifice Aura of Silence: Destroy target artifact or enchantment.

Ethereal Armor

Enchant creature
Enchanted creature gets +1/+1 for each enchantment you control and has first strike.

Gift of Immortality

Enchant creature
When enchanted creature dies, return that card to the battlefield under its owner's control. Return Gift of Immortality to the battlefield attached to that creature at the beginning of the next end step.

Thalakos Lowlands

{T}: Add {C}.
{T}: Add {W} or {U}. Thalakos Lowlands doesn't untap during your next untap step.

Archetype of Courage

Creatures you control have first strike.
Creatures your opponents control lose first strike and can't have or gain first strike.

Ancestral Mask

Enchant creature
Enchanted creature gets +2/+2 for each other enchantment on the battlefield.

Island

Freed from the Real

Enchant creature
{U}: Tap enchanted creature.
{U}: Untap enchanted creature.

Alseid of Life's Bounty

Lifelink
{1}, Sacrifice Alseid of Life's Bounty: Target creature or enchantment you control gains protection from the color of your choice until end of turn.

Eidolon of Blossoms

Constellation — Whenever Eidolon of Blossoms or another enchantment enters the battlefield under your control, draw a card.

Forest

Dawn Evangel

Whenever a creature dies, if an Aura you controlled was attached to it, return target creature card with mana value 2 or less from your graveyard to your hand.

Circle of Protection: Green

{1}: The next time a green source of your choice would deal damage to you this turn, prevent that damage.

Circle of Protection: Black

{1}: The next time a black source of your choice would deal damage to you this turn, prevent that damage.