Xolatoyac, the Smiling Flood

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.

Into the North

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

Valakut, the Molten Pinnacle

This land enters tapped.
Whenever a Mountain you control enters, if you control at least five other Mountains, you may have this land deal 3 damage to any target.
{T}: Add {R}.

Flubs, the Fool

You may play an additional land on each of your turns.
Whenever you play a land or cast a spell, draw a card if you have no cards in hand. Otherwise, discard a card.

Sheltered Thicket

({T}: Add {R} or {G}.)
This land enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Splash Portal

Exile target creature you control, then return it to the battlefield under its owner's control. If that creature is a Bird, Frog, Otter, or Rat, draw a card.

Snow-Covered Forest

Spire Barrage

Spire Barrage deals damage to any target equal to the number of Mountains you control.

Lingering Mirage

Enchant land
Enchanted land is an Island.
Cycling {2} ({2}, Discard this card: Draw a card.)

Snow-Covered Mountain

Blood Moon

Colossal Skyturtle

Flying, ward {2}
Channel — {2}{G}, Discard this card: Return target card from your graveyard to your hand.
Channel — {1}{U}, Discard this card: Return target creature to its owner's hand.

Vernal Bloom

Whenever a Forest is tapped for mana, its controller adds an additional {G}.

Realmwright

As this creature enters, choose a basic land type.
Lands you control are the chosen type in addition to their other types.

Rootpath Purifier

Lands you control and land cards in your library are basic.

Flow of Knowledge

Draw a card for each Island you control, then discard two cards.

Skred

Skred deals damage to target creature equal to the number of snow permanents you control.

Essence Flux

Exile target creature you control, then return that card to the battlefield under its owner's control. If it's a Spirit, put a +1/+1 counter on it.

Nature's Rhythm

Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.
Harmonize {X}{G}{G}{G}{G} (You may cast this card from your graveyard for its harmonize cost. You may tap a creature you control to reduce that cost by an amount of generic mana equal to its power. Then exile this spell.)

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Ice-Fang Coatl

Flash
Flying
When this creature enters, draw a card.
This creature has deathtouch as long as you control at least three other snow permanents.

Terramorphic Expanse

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

Have

Typhoon

Typhoon deals damage to each opponent equal to the number of Islands that player controls.

Highland Weald

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

Baleful Stare

Target opponent reveals their hand. You draw a card for each Mountain and red card in it.

Perennial Behemoth

You may play lands from your graveyard.
Unearth {G}{G} ({G}{G}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Sea's Claim

Enchant land (Target a land as you cast this. This card enters attached to that land.)
Enchanted land is an Island.

Withering Gaze

Target opponent reveals their hand. You draw a card for each Forest and green card in it.

Jaws of Stone

Jaws of Stone deals X damage divided as you choose among any number of targets, where X is the number of Mountains you control as you cast this spell.

Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

March from Velis Vel

Choose a nonbasic land type. Each land you control of that type becomes a copy of target creature you control until end of turn and gains haste until end of turn.
Flashback {4}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Rimewood Falls

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

Blur

Exile target creature you control, then return that card to the battlefield under its owner's control.
Draw a card.

Guardian of Tazeem

Flying
Landfall — Whenever a land you control enters, tap target creature an opponent controls. If that land is an Island, that creature doesn't untap during its controller's next untap step.

Wayward Swordtooth

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
You may play an additional land on each of your turns.
This creature can't attack or block unless you have the city's blessing.

Abundance

If you would draw a card, you may instead choose land or nonland and reveal cards from the top of your library until you reveal a card of the chosen kind. Put that card into your hand and put all other cards revealed this way on the bottom of your library in any order.

Crop Rotation

As an additional cost to cast this spell, sacrifice a land.
Search your library for a land card, put that card onto the battlefield, then shuffle.

Walk the Aeons

Buyback—Sacrifice three Islands. (You may sacrifice three Islands in addition to any other costs as you cast this spell. If you do, put this card into your hand as it resolves.)
Target player takes an extra turn after this one.

Koth, Fire of Resistance

+2: Search your library for a basic Mountain card, reveal it, put it into your hand, then shuffle.
−3: Koth deals damage to target creature equal to the number of Mountains you control.
−7: You get an emblem with "Whenever a Mountain you control enters, this emblem deals 4 damage to any target."

Roots of Life

As this enchantment enters, choose Island or Swamp.
Whenever a land of the chosen type an opponent controls becomes tapped, you gain 1 life.

Rimefeather Owl

Flying
Rimefeather Owl's power and toughness are each equal to the number of snow permanents on the battlefield.
{1}{S}: Put an ice counter on target permanent.
Permanents with ice counters on them are snow.

Prismatic Omen

Lands you control are every basic land type in addition to their other types.

Spawn of Thraxes

Flying
When this creature enters, it deals damage to any target equal to the number of Mountains you control.

Suspend

Exile target creature and put two time counters on it. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, they remove a time counter. When the last is removed, they may play it without paying its mana cost. If it's a creature, it has haste.)

Ramunap Excavator

Flow of Ideas

Eluge, the Shoreless Sea

Eluge's power and toughness are each equal to the number of Islands you control.
Whenever Eluge enters or attacks, put a flood counter on target land. It's an Island in addition to its other types for as long as it has a flood counter on it.
The first instant or sorcery spell you cast each turn costs {U} (or {1}) less to cast for each land you control with a flood counter on it.

Lifetap

Whenever a Forest an opponent controls becomes tapped, you gain 1 life.

Planar Incision

Exile target artifact or creature, then return it to the battlefield under its owner's control with a +1/+1 counter on it.

Omo, Queen of Vesuva

Whenever Omo enters or attacks, put an everything counter on each of up to one target land and up to one target creature.
Each land with an everything counter on it is every land type in addition to its other types.
Each nonland creature with an everything counter on it is every creature type.

Volcanic Eruption

Destroy X target Mountains. Volcanic Eruption deals damage to each creature and each player equal to the number of Mountains put into a graveyard this way.

Ureni, the Song Unending

Flying, protection from white and from black
When Ureni enters, it deals X damage divided as you choose among any number of target creatures and/or planeswalkers your opponents control, where X is the number of lands you control.

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Spreading Seas

Enchant land
When this Aura enters, draw a card.
Enchanted land is an Island.

Splendid Reclamation

Return all land cards from your graveyard to the battlefield tapped.

Scapeshift

Sacrifice any number of lands. Search your library for up to that many land cards, put them onto the battlefield tapped, then shuffle.

Fruition

You gain 1 life for each Forest on the battlefield.

The Flood of Mars

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Water Always Wins — Whenever this creature attacks, put a flood counter on another target creature or land. If it's a creature, it becomes a copy of this creature. If it's a land, it becomes an Island in addition to its other types.

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Rampant Growth

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

Staff of Titania

Equipped creature gets +X/+X, where X is the number of Forests you control.
Whenever equipped creature attacks, create a 1/1 green Forest Dryad land creature token. (It's affected by summoning sickness.)
Equip {3}

Thoughtleech

Whenever an Island an opponent controls becomes tapped, you may gain 1 life.

Stormtide Leviathan

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.

Regrowth

Return target card from your graveyard to your hand.

Summer Bloom

You may play up to three additional lands this turn.

Teferi's Time Twist

Exile target permanent you control. Return that card to the battlefield under its owner's control at the beginning of the next end step. If it enters as a creature, it enters with an additional +1/+1 counter on it.

Glacierwood Siege

As this enchantment enters, choose Temur or Sultai.
• Temur — Whenever you cast an instant or sorcery spell, target player mills four cards.
• Sultai — You may play lands from your graveyard.

Command Tower

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

Path of Ancestry

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.)

Elsewhere Flask

When this artifact enters, draw a card.
Sacrifice this artifact: Choose a basic land type. Each land you control becomes that type until end of turn.

Marit Lage's Slumber

Whenever Marit Lage's Slumber or another snow permanent you control enters, scry 1.
At the beginning of your upkeep, if you control ten or more snow permanents, sacrifice Marit Lage's Slumber. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

Eternal Flame

Eternal Flame deals X damage to target opponent or planeswalker and half X damage, rounded up, to you, where X is the number of Mountains you control.

Conduit of Worlds

You may play lands from your graveyard.
{T}: Choose target nonland permanent card in your graveyard. If you haven't cast a spell this turn, you may cast that card. If you do, you can't cast additional spells this turn. Activate only as a sorcery.

Akoum Hellkite

Flying
Landfall — Whenever a land you control enters, this creature deals 1 damage to any target. If that land is a Mountain, this creature deals 2 damage instead.

Glacial Crevasses

Sacrifice a snow Mountain: Prevent all combat damage that would be dealt this turn.

Eternal Witness

When this creature enters, you may return target card from your graveyard to your hand.

Overlord of the Hauntwoods

Impending 4—{1}{G}{G} (If you cast this spell for its impending cost, it enters with four time counters and isn't a creature until the last is removed. At the beginning of your end step, remove a time counter from it.)
Whenever this permanent enters or attacks, create a tapped colorless land token named Everywhere that is every basic land type.

Volatile Fjord

({T}: Add {U} or {R}.)
This land enters tapped.

Cinder Glade

({T}: Add {R} or {G}.)
This land enters tapped unless you control two or more basic lands.

Highland Forest

({T}: Add {R} or {G}.)
This land enters tapped.

Oran-Rief Hydra

Trample
Landfall — Whenever a land you control enters, put a +1/+1 counter on this creature. If that land is a Forest, put two +1/+1 counters on this creature instead.

Auroral Procession

Escape Tunnel

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
{T}, Sacrifice this land: Target creature with power 2 or less can't be blocked this turn.

Quicksilver Fountain

At the beginning of each player's upkeep, that player puts a flood counter on target non-Island land they control of their choice. That land is an Island for as long as it has a flood counter on it.
At the beginning of each end step, if all lands on the battlefield are Islands, remove all flood counters from them.

Frontier Bivouac

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

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Exotic Orchard

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

Evolving Wilds

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Blizzard Strix

Flash
Flying
When this creature enters, if you control another snow permanent, exile target permanent other than this creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Carpet of Flowers

At the beginning of each of your main phases, if you haven't added mana with this ability this turn, you may add X mana of any one color, where X is the number of Islands target opponent controls.

Sylvan Scrying

Search your library for a land card, reveal it, put it into your hand, then shuffle.

Loot, the Pathfinder

Double strike, vigilance, haste
Exhaust — {G}, {T}: Add three mana of any one color. (Activate each exhaust ability only once.)
Exhaust — {U}, {T}: Draw three cards.
Exhaust — {R}, {T}: Loot deals 3 damage to any target.

Song of Creation

You may play an additional land on each of your turns.
Whenever you cast a spell, draw two cards.
At the beginning of your end step, discard your hand.