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.)

Jade Bearer

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

Jace's Sentinel

As long as you control a Jace planeswalker, this creature gets +1/+0 and can't be blocked.

Kumena's Speaker

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

Watertrap Weaver

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

Malfunction

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

Island

Jace, Ingenious Mind-Mage

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

Dissenter's Deliverance

Destroy target artifact.
Cycling {G} ({G}, Discard this card: Draw a card.)

Deeproot Elite

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

Crashing Tide

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

Cancel

Herald of Secret Streams

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

One With the Wind

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

Dive Down

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

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.

Castaway's Despair

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

River Heralds' Boon

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

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.)

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.

Woodland Stream

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

Tempest Caller

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

Vineshaper Mystic

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

Forest

Shaper Apprentice

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

Cobbled Wings

Equipped creature has flying.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)