Augur of Bolas

When Augur of Bolas enters the battlefield, look at the top three cards of your library. You may reveal an instant or sorcery card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Simic Signet

Saw It Coming

Counter target spell.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

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.

Triton Waverider

Constellation — Whenever an enchantment enters the battlefield under your control, Triton Waverider gains flying until end of turn.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Sage of the Falls

Whenever Sage of the Falls or another non-Human creature enters the battlefield under your control, you may draw a card. If you do, discard a card.

Kiora's Follower

Explore

You may play an additional land this turn.
Draw a card.

Displacement Wave

Return all nonland permanents with mana value X or less to their owners' hands.

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Tempest Caller

When Tempest Caller enters the battlefield, tap all creatures target opponent controls.

Myriad Landscape

Myriad Landscape enters the battlefield tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Master of Waves

Protection from red
Elemental creatures you control get +1/+1.
When Master of Waves enters the battlefield, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Whirlpool Rider

When Whirlpool Rider enters the battlefield, shuffle the cards from your hand into your library, then draw that many cards.

Jungle Delver

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

Strength of the Tajuru

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose target creature, then choose another target creature for each time this spell was kicked. Put X +1/+1 counters on each of them.

Biogenic Upgrade

Distribute three +1/+1 counters among one, two, or three target creatures, then double the number of +1/+1 counters on each of those creatures.

Behold the Multiverse

Scry 2, then draw two cards.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Enclave Elite

Multikicker {1}{U} (You may pay an additional {1}{U} any number of times as you cast this spell.)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Enclave Elite enters the battlefield with a +1/+1 counter on it for each time it was kicked.

Swimmer in Nightmares

Swimmer in Nightmares gets +3/+0 as long as there are ten or more cards in a single graveyard.
Swimmer in Nightmares can't be blocked as long as you control an Ashiok planeswalker.

Island

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Fallowsage

Whenever Fallowsage becomes tapped, you may draw a card.

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.

Nevinyrral's Disk

Nevinyrral's Disk enters the battlefield tapped.
{1}, {T}: Destroy all artifacts, creatures, and enchantments.

Ravenform

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Aether Gale

Return six target nonland permanents to their owners' hands.

Baral's Expertise

Return up to three target artifacts and/or creatures to their owners' hands.
You may cast a spell with mana value 4 or less from your hand without paying its mana cost.

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.

Coralhelm Chronicler

Whenever you cast a kicked spell, draw a card, then discard a card.
When Coralhelm Chronicler enters the battlefield, look at the top five cards of your library. You may reveal a card with a kicker ability from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Merfolk of the Pearl Trident

Sol Ring

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Storm Sculptor

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

Thriving Grove

Thriving Grove enters the battlefield tapped.
As Thriving Grove enters the battlefield, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Tidal Courier

When Tidal Courier enters the battlefield, 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}: Tidal Courier gains flying until end of turn.

Precognitive Perception

Draw three cards.
Addendum — If you cast this spell during your main phase, instead scry 3, then draw three cards.

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.

Merrow Reejerey

Other Merfolk creatures you control get +1/+1.
Whenever you cast a Merfolk spell, you may tap or untap target permanent.

Seascape Aerialist

Whenever Seascape Aerialist or another Ally enters the battlefield under your control, you may have Ally creatures you control gain flying until end of turn.

Vodalian Arcanist

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

Thornwood Falls

Thornwood Falls enters the battlefield tapped.
When Thornwood Falls enters the battlefield, you gain 1 life.
{T}: Add {G} or {U}.

Negate

Bloodspore Thrinax

Devour 1 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with that many +1/+1 counters on it.)
Each other creature you control enters the battlefield with an additional X +1/+1 counters on it, where X is the number of +1/+1 counters on Bloodspore Thrinax.

Depart the Realm

Return target nonland permanent to its owner's hand.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Font of Fertility

{1}{G}, Sacrifice Font of Fertility: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Simic Guildgate

Simic Guildgate enters the battlefield tapped.
{T}: Add {G} or {U}.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Rain of Revelation

Thriving Isle

Thriving Isle enters the battlefield tapped.
As Thriving Isle enters the battlefield, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

River Merfolk

{U}: River Merfolk gains mountainwalk until end of turn. (It can't be blocked as long as defending player controls a Mountain.)

Rampant Growth

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

Triton Fortune Hunter

Heroic — Whenever you cast a spell that targets Triton Fortune Hunter, draw a card.

Ridgescale Tusker

When Ridgescale Tusker enters the battlefield, put a +1/+1 counter on each other creature you control.

Wild Onslaught

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Put a +1/+1 counter on each creature you control. If this spell was kicked, put two +1/+1 counters on each creature you control instead.

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Whelming Wave

Return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.

Jade Guardian

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

Razorfin Abolisher

{1}{U}, {T}: Return target creature with a counter on it to its owner's hand.

Blighted Woodland

{T}: Add {C}.
{3}{G}, {T}, Sacrifice Blighted Woodland: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Harbinger of the Tides

You may cast Harbinger of the Tides as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
When Harbinger of the Tides enters the battlefield, you may return target tapped creature an opponent controls to its owner's hand.

Decree of Savagery

Put four +1/+1 counters on each creature you control.
Cycling {4}{G}{G} ({4}{G}{G}, Discard this card: Draw a card.)
When you cycle Decree of Savagery, you may put four +1/+1 counters on target creature.

Forest

Strength of the Pack

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

Epiphany at the Drownyard

Reveal the top X plus one cards of your library and separate them into two piles. An opponent chooses one of those piles. Put that pile into your hand and the other into your graveyard.

Search for Tomorrow

Search your library for a basic land card, put it onto the battlefield, then shuffle.
Suspend 2—{G} (Rather than cast this card from your hand, you may pay {G} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Towering-Wave Mystic

Whenever Towering-Wave Mystic deals damage, target player mills that many cards.

Seafloor Oracle

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

Talrand, Sky Summoner

Whenever you cast an instant or sorcery spell, create a 2/2 blue Drake creature token with flying.

Merfolk Seastalkers

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
{2}{U}: Tap target creature without flying.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Triton Shorestalker

Vorel of the Hull Clade

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

Vodalian Merchant

When Vodalian Merchant enters the battlefield, draw a card, then discard a card.