Vodalian Arcanist

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

Storm Sculptor

Storm Sculptor can't be blocked.
When Storm Sculptor enters, return a creature you control to its owner's hand.

Coral Merfolk

Tishana's Wayfinder

When Tishana's Wayfinder 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.)

Merfolk Spy

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Merfolk Spy deals combat damage to a player, that player reveals a card at random from their hand.

Tazeem Roilmage

Kicker {4} (You may pay an additional {4} as you cast this spell.)
When Tazeem Roilmage enters, if it was kicked, return target instant or sorcery card from your graveyard to your hand.

Wavecrash Triton

Heroic — Whenever you cast a spell that targets Wavecrash Triton, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Cascade Seer

When Cascade Seer enters, scry X, where X is the number of creatures in your party. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)

Jadecraft Artisan

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

Kumena, Tyrant of Orazca

Tap another untapped Merfolk you control: Kumena, Tyrant of Orazca 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.

Jade Bearer

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

Triton Shorethief

Jungle Delver

{3}{G}: Put a +1/+1 counter on Jungle Delver.

Giltgrove Stalker

Giltgrove Stalker can't be blocked by creatures with power 2 or less.

Salvager of Secrets

When Salvager of Secrets enters, return target instant or sorcery card from your graveyard to your hand.