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

Return target creature to its owner's hand. If it was tapped, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

When Brokers Hideout enters the battlefield, sacrifice it. When you do, search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Whenever Careening Mine Cart attacks, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

When Cenote Scout enters the battlefield, 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.)

{1}{G}, {T}: This turn, each creature you control enters the battlefield with an additional +1/+1 counter on it.

{1}{U}, {T}: Move a +1/+1 counter from target creature you control onto another target creature you control.

Target player draws three cards. Then that player discards two cards unless they discard a land card.

Counter target spell.

Flash

Enchant creature

Enchanted creature loses all abilities and is a black Skeleton creature with base power and toughness 1/1. (It loses all other card types and creature types.)

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

Counter target creature spell.

Draw a card.

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

When Forerunner of the Heralds enters the battlefield, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.

Whenever another Merfolk enters the battlefield under your control, put a +1/+1 counter on Forerunner of the Heralds.

({T}: Add {G}.)

({T}: Add {G}.)

{T}: Add {C}.

Other Caves you control have "{T}, Pay 1 life: Add one mana of any color."

Choose one --

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

• Return target Cave card from your graveyard to the battlefield tapped.

Equipped creature has "You may look at the top card of your library any time" and "Whenever this creature attacks, 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 that creature, then put the card back or put it into your graveyard.)

Equip {2}

At the beginning of combat on your turn, each Merfolk 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 exploring creature, then put the card back or put it into your graveyard.)

Whenever Hakbal of the Surging Soul attacks, you may put a land card from your hand onto the battlefield. If you don't, draw a card.

Hidden Cataract enters the battlefield tapped.

{T}: Add {U}.

{4}{U}, {T}, Sacrifice Hidden Cataract: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Hidden Nursery enters the battlefield tapped.

{T}: Add {G}.

{4}{G}, {T}, Sacrifice Hidden Nursery: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

When Jadelight Spelunker enters the battlefield, it explores X times. (To have it explore, 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 that creature, then put the card back or put it into your graveyard.)

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

{T}: Add {G}.

Whenever a creature you control explores, Merfolk Cave-Diver gets +1/+0 until end of turn and can't be blocked this turn.

{T}: Add {C}.

{1}, {T}, Sacrifice Mind Stone: Draw a card.

Counter target instant or sorcery spell.

Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Counter target noncreature spell.

Whenever a creature you control explores a land card, you may put a land card from your hand onto the battlefield tapped.

Whenever a creature you control explores a nonland card, put a +1/+1 counter on Nicanzil, Current Conductor.

Choose one --

• Destroy target artifact or enchantment.

• Target creature you control explores, then it explores again. (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 that creature, then put the card back or put it into your graveyard. Then repeat this process.)

Creatures you control get +3/+3 until end of turn. Each creature your opponents control blocks this turn if able.

{T}: Add {C}.

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

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

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

Counter target spell. If that spell is countered this way, put it into its owner's hand instead of into that player's graveyard.

Draw a card.

River Sneak can't be blocked.

Whenever another Merfolk enters the battlefield under your control, River Sneak gets +1/+1 until end of turn.

Vigilance

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

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

When Silvergill Adept enters the battlefield, draw a card.

{1}, {T}: Add {G}{U}.

{T}: Add {C}{C}.

When Spelunking enters the battlefield, draw a card, then you may put a land card from your hand onto the battlefield. If you put a Cave onto the battlefield this way, you gain 4 life.

Lands you control enter the battlefield untapped.

Svyelun of Sea and Sky has indestructible as long as you control at least two other Merfolk.

Whenever Svyelun attacks, draw a card.

Other Merfolk you control have ward {1}. (Whenever another Merfolk you control becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Flash

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

Target permanent you control gains hexproof and indestructible until end of turn. You gain 2 life. (A permanent with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Thornwood Falls enters the battlefield tapped.

When Thornwood Falls enters the battlefield, you gain 1 life.

{T}: Add {G} or {U}.

Flash

When Tishana's Tidebinder enters the battlefield, counter up to one target activated or triggered ability. If an ability of an artifact, creature, or planeswalker is countered this way, that permanent loses all abilities for as long as Tishana's Tidebinder remains on the battlefield. (Mana abilities can't be targeted.)

If a creature you control would explore, instead you scry 1, then that creature explores.

When Twists and Turns enters the battlefield, target creature you control explores.

When a land enters the battlefield under your control, if you control seven or more lands, transform Twists and Turns.

(Transforms from Twists and Turns.)

{T}: Add {G}.

{3}{G}, {T}: Look at the top four cards of your library. You may reveal a creature card from among them and put that card into your hand. Put the rest on the bottom of your library in a random order.

Enchant Forest

As Utopia Sprawl enters, choose a color.

Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.

Flying

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