River Sneak

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

Watertrap Weaver

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

Tempest Caller

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

Kumena's Speaker

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

River's Rebuke

Return all nonland permanents target player controls to their owner's hand.

Release to the Wind

Exile target nonland permanent. For as long as that card remains exiled, its owner may cast it without paying its mana cost.

Emergent Growth

Target creature gets +5/+5 until end of turn and must be blocked this turn if able.

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.)

Kopala, Warden of Waves

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.

Seafloor Oracle

Whenever a Merfolk you control deals combat damage to a player, draw a card.

Crashing Tide

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

Winged Temple of Orazca

(Transforms from Hadana's Climb.)
{T}: Add one mana of any color.
{1}{G}{U}, {T}: Target creature you control gains flying and gets +X/+X until end of turn, where X is its power.

Hadana's Climb

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control. Then if that creature has three or more +1/+1 counters on it, transform Hadana's Climb.

Hadana's Climb // Winged Temple of Orazca

River Heralds' Boon

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

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.

Silvergill Adept

As an additional cost to cast this spell, reveal a Merfolk card from your hand or pay {3}.
When this creature enters, draw a card.

Mist-Cloaked Herald

Unsummon

Return target creature to its owner's hand.

Vineshaper Mystic

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

Forerunner of the Heralds

When this creature enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.
Whenever another Merfolk you control enters, put a +1/+1 counter on this creature.

Deeproot Elite

Whenever another Merfolk you control enters, put a +1/+1 counter on target Merfolk you control.

Strength of the Pack

Put two +1/+1 counters on each creature you control.

Hinterland Harbor

This land enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Jade Bearer

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

Forest

Sentinel of the Nameless City

Vigilance
Whenever this creature enters or attacks, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")

Herald of Secret Streams

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

Slice in Twain

Destroy target artifact or enchantment.
Draw a card.

Expel from Orazca

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Return target nonland permanent to its owner's hand. If you have the city's blessing, you may put that permanent on top of its owner's library instead.

Grasping Current

Return up to two target creatures to their owner's hand.
Search your library and/or graveyard for a card named Jace, Ingenious Mind-Mage, reveal it, and put it into your hand. If you searched your library this way, shuffle.

Aquatic Incursion

When this enchantment enters, create two 1/1 blue Merfolk creature tokens with hexproof. (They can't be the targets of spells or abilities your opponents control.)
{3}{U}: Target Merfolk can't be blocked this turn.

Island

Unclaimed Territory

As this land enters, 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.

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.

Blinding Fog

Prevent all damage that would be dealt to creatures this turn. Creatures you control gain hexproof until end of turn. (They can't be the targets of spells or abilities your opponents control.)

Castaway's Despair

Kumena, Tyrant of Orazca

Tap another untapped Merfolk you control: Kumena can't be blocked this turn.
Tap three untapped Merfolk you control: Draw a card.
Tap five untapped Merfolk you control: Put a +1/+1 counter on each Merfolk you control.

Aggressive Urge

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

Deeproot Pilgrimage

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

Tishana, Voice of Thunder

Tishana's power and toughness are each equal to the number of cards in your hand.
You have no maximum hand size.
When Tishana enters, draw a card for each creature you control.

Azcanta, the Sunken Ruin

(Transforms from Search for Azcanta.)
{T}: Add {U}.
{2}{U}, {T}: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Search for Azcanta

At the beginning of your upkeep, surveil 1. Then if you have seven or more cards in your graveyard, you may transform Search for Azcanta. (Look at the top card of your library. You may put that card into your graveyard.)

Search for Azcanta // Azcanta, the Sunken Ruin

Merfolk Mistbinder

Jace, Ingenious Mind-Mage

+1: Draw a card.
+1: Untap all creatures you control.
−9: Gain control of up to three target creatures.

Waterwind Scout

Flying
When this creature enters, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")

Merfolk Branchwalker

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.)

Shapers' Sanctuary

Whenever a creature you control becomes the target of a spell or ability an opponent controls, you may draw a card.

Woodland Stream

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

Deeproot Waters

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.)

Vineglimmer Snarl

As this land enters, you may reveal a Forest or Island card from your hand. If you don't, this land enters tapped.
{T}: Add {G} or {U}.