Thassa, God of the Sea

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.

Ominous Seas

Whenever you draw a card, put a foreshadow counter on this enchantment.
Remove eight foreshadow counters from this enchantment: Create an 8/8 blue Kraken creature token.
Cycling {2} ({2}, Discard this card: Draw a card.)

Druid Class

(Gain the next level as a sorcery to add its ability.)
Landfall — Whenever a land you control enters, you gain 1 life.
{2}{G}: Level 2
You may play an additional land on each of your turns.
{4}{G}: Level 3
When this Class becomes level 3, target land you control becomes a creature with haste and "This creature's power and toughness are each equal to the number of lands you control." It's still a land.

Starlit Mantle

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature you control
When this Aura enters, enchanted creature gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)
Enchanted creature gets +1/+1.

Ichthyomorphosis

Enchant creature
Enchanted creature loses all abilities and is a blue Fish with base power and toughness 0/1.

Tatyova, Steward of Tides

Land creatures you control have flying.
Whenever a land you control enters, if you control seven or more lands, up to one target land you control becomes a 3/3 Elemental creature with haste. It's still a land.

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.)

Path of Ancestry

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.)

Gretchen Titchwillow

{2}{G}{U}: Draw a card. You may put a land card from your hand onto the battlefield.

Crashing Tide

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

Mantle of the Wolf

Enchant creature
Enchanted creature gets +4/+4.
When this Aura is put into a graveyard from the battlefield, create two 2/2 green Wolf creature tokens.

Harbinger of the Seas

Emperor Mihail II

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.

Eutropia the Twice-Favored

Constellation — Whenever an enchantment you control enters, put a +1/+1 counter on target creature. That creature gains flying until end of turn.

Tishana's Tidebinder

Flash
When this creature enters, counter up to one target activated or triggered ability. If an ability of an artifact, creature, or planeswalker is countered this way, that permanent loses all abilities for as long as this creature remains on the battlefield. (Mana abilities can't be targeted.)

Harmonious Emergence

Enchant land you control
Enchanted land is a 4/5 green Spirit creature with vigilance and haste. It's still a land.
If enchanted land would be destroyed, instead sacrifice this Aura and that land gains indestructible until end of turn.

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.

Moonlit Scavengers

When this creature enters, if you control an artifact or enchantment, return target creature an opponent controls to its owner's hand.

Sea God's Scorn

Return up to three target creatures and/or enchantments to their owners' hands.

Thornwood Falls

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {G} or {U}.

Nael, Avizoa Aeronaut

Flying
Domain — Whenever Nael deals combat damage to a player, look at the top X cards of your library, where X is the number of basic land types among lands you control. Put up to one of them on top of your library and the rest on the bottom in a random order. Then if there are five basic land types among lands you control, draw a card.

Forest

Triton Shorethief

Soporific Springs

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {U}.

Sink into Stupor

Return target spell or nonland permanent an opponent controls to its owner's hand.

Sink into Stupor // Soporific Springs

Godhunter Octopus

This creature can't attack unless defending player controls an enchantment or an enchanted permanent.

Thassa's Devourer

Constellation — Whenever this creature or another enchantment you control enters, target player mills two cards.

Inspire Awe

Prevent all combat damage that would be dealt this turn except combat damage that would be dealt by enchanted creatures and enchantment creatures. Scry 2.

Triton Cavalry

Heroic — Whenever you cast a spell that targets this creature, you may return target enchantment to its owner's hand.

Island

Decanter of Endless Water

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

Plummet

Voyage's End

Return target creature to its owner's hand. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Gray Harbor Merfolk

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

Caller of Gales

{1}{U}, {T}: Target creature gains flying until end of turn.

Deeproot Pilgrimage

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

Roil Cartographer

Landfall — Whenever a land you control enters, you get {E} (an energy counter).
{T}, Pay six {E}: Draw three cards.

Sky Diamond

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

Sage of Mysteries

Constellation — Whenever an enchantment you control enters, target player mills two cards.

Bronze Walrus

When this creature enters, 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.)
{T}: Add one mana of any color.

Sol Ring

Pirate Ship

This creature can't attack unless defending player controls an Island.
{T}: This creature deals 1 damage to any target.
When you control no Islands, sacrifice this creature.

Rootrider Faun

{T}: Add {G}.
{1}, {T}: Add one mana of any color.

Nyxborn Seaguard

Wash Away

Cleave {1}{U}{U} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Counter target spell [that wasn't cast from its owner's hand].

Seeker of Sunlight

{2}{G}: This creature explores. Activate only as a sorcery. (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.)

Thirst for Meaning

Draw three cards. Then discard two cards unless you discard an enchantment card.

Altar of the Pantheon

Your devotion to each color and each combination of colors is increased by one.
{T}: Add one mana of any color. If you control a God, a Demigod, or a legendary enchantment, you gain 1 life.

Commune with Spirits

Look at the top four cards of your library. You may reveal an enchantment or land card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Nylea's Forerunner

Trample
Other creatures you control have trample.

Lord of Atlantis

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

Brave the Wilds

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
If this spell was bargained, target land you control becomes a 3/3 Elemental creature with haste that's still a land.
Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Utopia Sprawl

Enchant Forest
As this Aura enters, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.

Triton Waverider

Constellation — Whenever an enchantment you control enters, this creature gains flying until end of turn.

Self-Reflection

Create a token that's a copy of target creature you control.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Thassa's Intervention

Choose one —
• Look at the top X cards of your library. Put up to two of them into your hand and the rest on the bottom of your library in a random order.
• Counter target spell unless its controller pays twice {X}.

Air-Cult Elemental

Flying
Whirlwind — When this creature enters, return up to one other target creature to its owner's hand.

Omen of the Sea

Flash (You may cast this spell any time you could cast an instant.)
When this enchantment enters, scry 2, then draw a card.
{2}{U}, Sacrifice this enchantment: 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.)

Dragon Turtle

Flash
Drag Below — When this creature enters, tap it and up to one target creature an opponent controls. They don't untap during their controllers' next untap steps.

Blossoming Tortoise

Whenever this creature enters or attacks, mill three cards, then return a land card from your graveyard to the battlefield tapped.
Activated abilities of lands you control cost {1} less to activate.
Land creatures you control get +1/+1.

Roaring Earth

Landfall — Whenever a land you control enters, put a +1/+1 counter on target creature or Vehicle you control.
Channel — {X}{G}{G}, Discard this card: Put X +1/+1 counters on target land you control. It becomes a 0/0 green Spirit creature with haste. It's still a land.

Ancestral Reminiscence

Nyx Lotus

Nyx Lotus enters tapped.
{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.)

Triton Shorestalker

High Tide

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

Enigmatic Incarnation

At the beginning of your end step, you may sacrifice another enchantment. If you do, search your library for a creature card with mana value equal to 1 plus the sacrificed enchantment's mana value, put that card onto the battlefield, then shuffle.

Warbriar Blessing

Enchant creature you control
When this Aura enters, enchanted creature fights up to one target creature you don't control. (Each deals damage equal to its power to the other.)
Enchanted creature gets +0/+2.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

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."

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.