The Lost Caverns of Ixalan Commander

Legendary Creature — Merfolk Scout

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

Hakbal of the Surging Soul

Instant

Return all attacking creatures to their owner's hand.

Aetherize

Land

{T}: Add {C}.
{G}{U}, {T}: You may cast spells this turn as though they had flash.

Alchemist's Refuge

Artifact

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

Arcane Signet

Beast

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Beast Within

Creature — Merfolk Wizard Mutant

{1}{U}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on this creature, draw a card, then discard a card.

Benthic Biomancer

Enchantment

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.

Branching Evolution

Sorcery

Descend 8 — When you cast this spell, if there are eight or more permanent cards in your graveyard, copy this spell twice. You may choose new targets for the copies.
Return target permanent card from your graveyard to your hand. Exile Bygone Marvels.

Bygone Marvels

Creature — Merfolk Rogue

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever this creature deals combat damage to a player, you may draw that many cards.

Cold-Eyed Selkie

Tower Winder

Command Tower

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Commander's Sphere

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Each player shuffles their hand and graveyard into their library, then draws seven cards.

Memory

Put target spell or nonland permanent into its owner's library second from the top.

Commit

Creature — Merfolk Soldier

Level up {1} ({1}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 2-3
3/3
Flying
LEVEL 4+
4/4
Flying
Other Merfolk creatures you control get +1/+1.

Coralhelm Commander

Boar

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Curse of the Swine

Creature — Merfolk Warrior

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

Deeproot Elite

Creature — Merfolk Druid

Merfolk and Druid cards in your graveyard have retrace. (You may cast cards with retrace from your graveyard by discarding a land card in addition to paying their other costs.)

Deeproot Historian

Merfolk

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.)

Deeproot Waters

Legendary Creature — Merfolk Noble

You may look at the top card of your library any time.
You may cast Merfolk spells from the top of your library.
Whenever you cast a Merfolk spell, you may pay {1}. If you do, create a 1/1 blue Merfolk creature token.

Emperor Mihail II

Creature — Elf Druid

Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Evolution Sage

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

Explore

The Lost Caverns of Ixalan

Gilt-Leaf Alchemist

Basic Land — Forest

Forest

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

Growth Spiral

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Hardened Scales

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

Herald of Secret Streams

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

Hinterland Harbor

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.)

Inspiring Call

Basic Land — Island

Island

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Karn's Bastion

As this enchantment enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Kindred Discovery

Creature — Merfolk

Kiora's Follower

Sorcery — Arcane

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Kodama's Reach

Legendary Creature — Merfolk Wizard

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.

Kopala, Warden of Waves

Legendary Creature — Merfolk Shaman

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.

Kumena, Tyrant of Orazca

This land enters tapped.
{T}: Add {G}.
Graft 1 (This land enters with a +1/+1 counter on it. Whenever a creature enters, you may move a +1/+1 counter from this land onto it.)

Llanowar Reborn

Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Master of the Pearl Trident

Creature — Merfolk Scout

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

Merfolk Cave-Diver

Creature — Merfolk Shaman

Merfolk Mistbinder

Creature — Merfolk Mutant

Flying
When this creature enters, put a +1/+1 counter on target creature you control.
{3}{G}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Merfolk Skydiver

Creature — Merfolk Noble

Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.

Merfolk Sovereign

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

Merrow Reejerey

Artifact Creature — Shapeshifter

As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
Each other creature you control of the chosen type enters with an additional +1/+1 counter on it.

Metallic Mimic

Copy

Creature — Merfolk Wizard

Flying
Other Merfolk you control get +1/+0 and have flying.
Encore {5}{U}{U} ({5}{U}{U}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Mist Dancer

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
This land enters tapped.
{T}: Add {G}.
{G}, {T}: You may play the exiled card without paying its mana cost if creatures you control have total power 10 or greater.

Mosswort Bridge

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

Myriad Landscape

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.

Nicanzil, Current Conductor

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Path of Ancestry

Prime Speaker Zegana enters with X +1/+1 counters on it, where X is the greatest power among other creatures you control.
When Prime Speaker Zegana enters, draw cards equal to its power.

Prime Speaker Zegana

Choose two —
• Return target creature or planeswalker to its owner's hand.
• Counter target artifact or enchantment spell.
• Put two +1/+1 counters on target creature.
• Target player shuffles up to three target cards from their graveyard into their library.

Quandrix Command

Frog Lizard

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Rapid Hybridization

Bird

Foretell

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.)

Ravenform

Creature — Shapeshifter

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Realmwalker

As this enchantment enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Reflections of Littjara

You have no maximum hand size.
{T}: Add {C}.

Reliquary Tower

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

Ripples of Potential

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Rogue's Passage

Exile target artifact or enchantment. Put X +1/+1 counters on target creature you control, where X is the mana value of the permanent exiled this way.

Ruinous Intrusion

Each other Wizard creature you control enters with an additional +1/+1 counter on it.
{2}, Remove a +1/+1 counter from a creature you control: Draw a card.

Sage of Fables

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

Seafloor Oracle

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 or activate an ability of a creature source of the chosen type.

Secluded Courtyard

{1}{G}{U}: Put a +1/+1 counter on target creature you control.
Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on this enchantment.
At the beginning of your upkeep, if this enchantment has twenty or more growth counters on it, you win the game.

Simic Ascendancy

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {G}{U}.

Simic Growth Chamber

Simic Signet

Flash
When this creature enters, put a shield counter on another target creature you control. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
You may cast Merfolk spells as though they had flash.

Singer of Swift Rivers

Sol Ring

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Merfolk spells and Wizard spells you cast cost {1} less to cast.

Stonybrook Banneret

Whenever this creature becomes tapped, you may pay {1}{U}. If you do, return target permanent to its owner's hand.

Surgespanner

Legendary Creature — Merfolk God

Svyelun 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}.)

Svyelun of Sea and Sky

Artifact — Equipment

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Swiftfoot Boots

Legendary Creature — Merfolk Druid

Landfall — Whenever a land you control enters, you gain 1 life and draw a card.

Tatyova, Benthic Druid

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {G} or {U}.

Temple of Mystery

{T}: Add {C}{C}. Activate only if you control five or more lands.

Temple of the False God

Legendary Enchantment Creature — God

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.

Thassa, God of the Sea

Kicker {X}. X can't be 0. (You may pay an additional {X} as you cast this spell.)
Flying
When this creature enters, if it was kicked, gain control of target artifact with mana value X or less. If that artifact is an Equipment, attach it to this creature.

Thieving Skydiver

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.

Tishana, Voice of Thunder

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.")
If a creature you control would explore, instead it explores, then it explores again.

Topography Tracker

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever a creature you control with a +1/+1 counter on it dies, draw a card.

Tributary Instructor

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.

Unclaimed Territory

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}.

Vineglimmer Snarl

Legendary Creature — Human Merfolk

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

Vorel of the Hull Clade

Return each creature without a +1/+1 counter on it to its owner's hand.

Wave Goodbye

Legendary Creature — Salamander Serpent

Whenever Xolatoyac enters or attacks, put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it.
At the beginning of your end step, untap each permanent you control with a counter on it.

Xolatoyac, the Smiling Flood

When Zegana enters, if you control another creature with a +1/+1 counter on it, draw a card.
{4}{G}{U}: Adapt 4. (If this creature has no +1/+1 counters on it, put four +1/+1 counters on it.)
Each creature you control with a +1/+1 counter on it has trample.

Zegana, Utopian Speaker

Source: https://magic.wizards.com/en/news/announcements/the-lost-caverns-of-ixalan-commander-decklists

Type	%	#
Blue	63%	59
Green	37%	34
*Inner Circle

Type	%	#
White	8%	6
Blue	34%	24
Black	8%	6
Red	8%	6
Green	28%	20
Colorless	13%	9
*Outer Circle

Deck History