Headwater Sentries

Umara Entangler

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Vodalian Knights

First strike
This creature can't attack unless defending player controls an Island.
When you control no Islands, sacrifice this creature.
{U}: This creature gains flying until end of turn.

Mercurial Transformation

Until end of turn, target nonland permanent loses all abilities and becomes your choice of a blue Frog creature with base power and toughness 1/1 or a blue Octopus creature with base power and toughness 4/4.

Halimar Wavewatch

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.)

Giant Octopus

Shoreline Raider

Halimar Depths

This land enters tapped.
When this land enters, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

Rootwater Commando

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Lost in Thought

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated. Its controller may exile three cards from their graveyard for that player to ignore this effect until end of turn.

Coral Commando

Damping Matrix

Activated abilities of artifacts and creatures can't be activated unless they're mana abilities.

Merfolk of the Depths

Flash (You may cast this spell any time you could cast an instant.)

Torpor Orb

Creatures entering don't cause abilities to trigger.

Cursed Totem

Activated abilities of creatures can't be activated.

Arctic Merfolk

Kicker—Return a creature you control to its owner's hand. (You may return a creature you control to its owner's hand in addition to any other costs as you cast this spell.)
If this creature was kicked, it enters with a +1/+1 counter on it.

Wind Strider

Flash (You may cast this spell any time you could cast an instant.)
Flying

Maritime Guard

Gaea's Skyfolk

Muraganda Petroglyphs

Vodalian Soldiers

Coral Merfolk

Pithing Needle

As this artifact enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Skywatcher Adept

Level up {3} ({3}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
2/2
Flying
LEVEL 3+
4/2
Flying

Sandbar Merfolk

Cycling {2} ({2}, Discard this card: Draw a card.)

Glaring Spotlight

Creatures your opponents control with hexproof can be the targets of spells and abilities you control as though they didn't have hexproof.
{3}, Sacrifice this artifact: Creatures you control gain hexproof until end of turn and can't be blocked this turn.

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Sorcerous Spyglass

As this artifact enters, look at an opponent's hand, then choose any card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Merfolk Raiders

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)

Nyxborn Seaguard

Kindred Discovery

As this enchantment enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Triton Shorethief

Merfolk of the Pearl Trident

Sworn Guardian

Dance of the Skywise

Until end of turn, target creature you control becomes a blue Dragon Illusion with base power and toughness 4/4, loses all abilities, and gains flying.