Seek the Horizon

Search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Illusory Wrappings

Enchant creature
Enchanted creature has base power and toughness 0/2.

Divination

Vodalian Mindsinger

Kicker {1}{R} and/or {1}{G}
This creature enters with two +1/+1 counters on it for each time it was kicked.
When this creature enters, gain control of target creature with power less than this creature's power for as long as you control this creature.

Wind Strider

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

One With the Wind

Enchant creature
Enchanted creature gets +2/+2 and has flying.

Crashing Tide

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

Soul of the Rapids

Flying
Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Negate

Jade Bearer

When this creature enters, put a +1/+1 counter on another target Merfolk you control.

New Horizons

Enchant land
When this Aura enters, put a +1/+1 counter on target creature you control.
Enchanted land has "{T}: Add two mana of any one color."

Riverwise Augur

When this creature enters, draw three cards, then put two cards from your hand on top of your library in any order.

Perilous Voyage

Return target nonland permanent you don't control to its owner's hand. If its mana value was 2 or less, scry 2.

Shaper Apprentice

This creature has flying as long as you control another Merfolk.

Sworn Guardian

Aquitect's Will

Put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. If you control a Merfolk, draw a card.

Dramatic Reversal

Untap all nonland permanents you control.

Commander's Sphere

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

Headwater Sentries

Plummet

Jungleborn Pioneer

When this creature enters, create a 1/1 blue Merfolk creature token with hexproof. (It can't be the target of spells or abilities your opponents control.)

Waker of the Wilds

{X}{G}{G}: Put X +1/+1 counters on target land you control. That land becomes a 0/0 Elemental creature with haste. It's still a land.

Anticipate

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Tempest Caller

When this creature enters, tap all creatures target opponent controls.

Slinn Voda, the Rising Deep

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
When Slinn Voda enters, if it was kicked, return all creatures to their owners' hands except for Merfolk, Krakens, Leviathans, Octopuses, and Serpents.

Enter the Unknown

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.

Tidal Courier

When this creature enters, reveal the top four cards of your library. Put all Merfolk cards revealed this way into your hand and the rest on the bottom of your library in any order.
{3}{U}: This creature gains flying until end of turn.

Tishana's Wayfinder

When this creature enters, it 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 this creature, then put the card back or put it into your graveyard.)

Streambed Aquitects

{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.

River Sneak

This creature can't be blocked.
Whenever another Merfolk you control enters, this creature gets +1/+1 until end of turn.

Watertrap Weaver

When this creature enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Fertile Thicket

This land enters tapped.
When this land enters, you may look at the top five cards of your library. If you do, reveal up to one basic land card from among them, then put that card on top of your library and the rest on the bottom in any order.
{T}: Add {G}.

Verdant Rebirth

Until end of turn, target creature gains "When this creature dies, return it to its owner's hand."
Draw a card.

Mist-Cloaked Herald

Grow from the Ashes

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Search your library for a basic land card, put it onto the battlefield, then shuffle. If this spell was kicked, instead search your library for two basic land cards, put them onto the battlefield, then shuffle.

Essence Scatter

Caller of Gales

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

Oakenform

Enchant creature
Enchanted creature gets +3/+3.

River Heralds' Boon

Put a +1/+1 counter on target creature and a +1/+1 counter on up to one target Merfolk.

Woodland Stream

This land enters tapped.
{T}: Add {G} or {U}.

Forest

Scroll Thief

Whenever this creature deals combat damage to a player, draw a card.

Titanic Growth

Target creature gets +4/+4 until end of turn.

Waterknot

Enchant creature
When this Aura enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Cancel

Aggressive Urge

Target creature gets +1/+1 until end of turn.
Draw a card.

Root Snare

Prevent all combat damage that would be dealt this turn.

Mind

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Draw two cards.

Spring

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Spring // Mind

Gift of Paradise

Enchant land
When this Aura enters, you gain 3 life.
Enchanted land has "{T}: Add two mana of any one color."

River Darter

This creature can't be blocked by Dinosaurs.

Vineshaper Mystic

When this creature enters, put a +1/+1 counter on each of up to two target Merfolk you control.

Jungle Delver

{3}{G}: Put a +1/+1 counter on this creature.

Gilded Sentinel

Surge Mare

This creature can't be blocked by green creatures.
Whenever this creature deals damage to an opponent, you may draw a card. If you do, discard a card.
{1}{U}: This creature gets +2/-2 until end of turn.

Cartouche of Strength

Enchant creature you control
When this Aura enters, you may have enchanted creature fight target creature an opponent controls. (Each deals damage equal to its power to the other.)
Enchanted creature gets +1/+1 and has trample.

Shapers of Nature

{3}{G}: Put a +1/+1 counter on target creature.
{2}{U}, Remove a +1/+1 counter from a creature you control: Draw a card.

Vorel of the Hull Clade

{G}{U}, {T}: Double the number of each kind of counter on target artifact, creature, or land.

Vodalian Arcanist

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.

Jadecraft Artisan

When this creature enters, target creature gets +2/+2 until end of turn.

Blossoming Defense

Target creature you control gets +2/+2 and gains hexproof until end of turn.

Rootwater Hunter

{T}: This creature deals 1 damage to any target.

Jade Guardian

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
When this creature enters, put a +1/+1 counter on target Merfolk you control.

Tidal Warrior

{T}: Target land becomes an Island until end of turn.

Cold-Eyed Selkie

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

Salvager of Secrets

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

Island

Kumena's Speaker

This creature gets +1/+1 as long as you control another Merfolk or an Island.

Run Aground

Put target artifact or creature on top of its owner's library.

Swift Warden

Flash
When this creature enters, target Merfolk you control gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Giltgrove Stalker

This creature can't be blocked by creatures with power 2 or less.

Broken Bond

Destroy target artifact or enchantment. You may put a land card from your hand onto the battlefield.

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Frilled Sea Serpent

{5}{U}{U}: This creature can't be blocked this turn.

Arbor Armament

Put a +1/+1 counter on target creature. That creature gains reach until end of turn. (It can block creatures with flying.)