Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

The Red Terror

Advanced Species — Whenever a red source you control deals damage to one or more permanents and/or players, put a +1/+1 counter on The Red Terror.

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."

Crucible of Worlds

Downhill Charge

You may sacrifice a Mountain rather than pay this spell's mana cost.
Target creature gets +X/+0 until end of turn, where X is the number of Mountains you control.

Triple Triad

At the beginning of your upkeep, each player exiles the top card of their library. Until end of turn, you may play the card you own exiled this way and each other card exiled this way with lesser mana value than it without paying their mana costs.

Myriad Landscape

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.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Stolen Strategy

At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.

Torbran, Thane of Red Fell

If a red source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

Sabotender

Reach
Landfall — Whenever a land you control enters, this creature deals 1 damage to each opponent.

Eternity Vessel

This artifact enters with X charge counters on it, where X is your life total.
Landfall — Whenever a land you control enters, you may have your life total become the number of charge counters on this artifact.

Zektar Shrine Expedition

Landfall — Whenever a land you control enters, you may put a quest counter on this enchantment.
Remove three quest counters from this enchantment and sacrifice it: Create a 7/1 red Elemental creature token with trample and haste. Exile it at the beginning of the next end step.

Dwarven Mine

({T}: Add {R}.)
This land enters tapped unless you control three or more other Mountains.
When this land enters untapped, create a 1/1 red Dwarf creature token.

Nahiri's Lithoforming

Sacrifice X lands. For each land sacrificed this way, draw a card. You may play X additional lands this turn. Lands you control enter tapped this turn.

Mines of Moria

Mines of Moria enters tapped unless you control a legendary creature.
{T}: Add {R}.
{3}{R}, {T}, Exile three cards from your graveyard: Create two Treasure tokens.

Retreat to Valakut

Landfall — Whenever a land you control enters, choose one —
• Target creature gets +2/+0 until end of turn.
• Target creature can't block this turn.

Spitfire Lagac

Landfall — Whenever a land you control enters, this creature deals 1 damage to each opponent.

Akoum Hellhound

Landfall — Whenever a land you control enters, this creature gets +2/+2 until end of turn.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Case of the Crimson Pulse

When this Case enters, discard a card, then draw two cards.
To solve — You have no cards in hand. (If unsolved, solve at the beginning of your end step.)
Solved — At the beginning of your upkeep, discard your hand, then draw two cards.

Nesting Dragon

Flying
Landfall — Whenever a land you control enters, create a 0/2 red Dragon Egg creature token with defender and "When this token dies, create a 2/2 red Dragon creature token with flying and '{R}: This token gets +1/+0 until end of turn.'"

Highway Robbery

You may discard a card or sacrifice a land. If you do, draw two cards.
Plot {1}{R} (You may pay {1}{R} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Call the Mountain Chocobo

Search your library for a Mountain card, reveal it, put it into your hand, then shuffle. Create a 2/2 green Bird creature token with "Whenever a land you control enters, this token gets +1/+0 until end of turn."
Flashback {5}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Spawn of Thraxes

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

Hedron Rover

Maestros Theater

When this land enters, sacrifice it. When you do, search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Outpost Siege

As this enchantment enters, choose Khans or Dragons.
• Khans — At the beginning of your upkeep, exile the top card of your library. Until end of turn, you may play that card.
• Dragons — Whenever a creature you control leaves the battlefield, this enchantment deals 1 damage to any target.

There and Back Again

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Up to one target creature can't block for as long as you control this Saga. The Ring tempts you.
II — Search your library for a Mountain card, put it onto the battlefield, then shuffle.
III — Create Smaug, a legendary 6/6 red Dragon creature token with flying, haste, and "When Smaug dies, create fourteen Treasure tokens."

Vandalblast

Destroy target artifact you don't control.
Overload {4}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Mountain

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.

Seer's Sundial

Landfall — Whenever a land you control enters, you may pay {2}. If you do, draw a card.

Valakut Predator

Sardian Cliffstomper

As long as it's your turn and you control four or more Mountains, this creature gets +X/+0, where X is the number of Mountains you control.

Count on Luck

At the beginning of your upkeep, exile the top card of your library. You may play that card this turn.

Tunneling Geopede

Koth of the Hammer

+1: Untap target Mountain. It becomes a 4/4 red Elemental creature until end of turn. It's still a land.
−2: Add {R} for each Mountain you control.
−5: You get an emblem with "Mountains you control have '{T}: This land deals 1 damage to any target.'"

Skyclave Geopede

Trample
Landfall — Whenever a land you control enters, this creature gets +2/+2 until end of turn.

Bonehoard Dracosaur

Flying, first strike
At the beginning of your upkeep, exile the top two cards of your library. You may play them this turn. If you exiled a land card this way, create a 3/1 red Dinosaur creature token. If you exiled a nonland card this way, create a Treasure token.

Hedron Scrabbler

Landfall — Whenever a land you control enters, this creature gets +1/+1 until end of turn.

Moraug, Fury of Akoum

Each creature you control gets +1/+0 for each time it has attacked this turn.
Landfall — Whenever a land you control enters, if it's your main phase, there's an additional combat phase after this phase. At the beginning of that combat, untap all creatures you control.

Zell Dincht

You may play an additional land on each of your turns.
Zell Dincht gets +1/+0 for each land you control.
At the beginning of your end step, return a land you control to its owner's hand.

Wrenn's Resolve

Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

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}.

Tavern Brawler

Commander creatures you own have "At the beginning of your upkeep, exile the top card of your library. This creature gets +X/+0 until end of turn, where X is that card's mana value. You may play that card this turn."

Sol Ring

Adventuring Gear

Landfall — Whenever a land you control enters, equipped creature gets +2/+2 until end of turn.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Plated Geopede

First strike
Landfall — Whenever a land you control enters, this creature gets +2/+2 until end of turn.

Warped Space

Once each turn, you may pay {0} rather than pay the mana cost for a spell you cast from exile.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Charred Foyer

At the beginning of your upkeep, exile the top card of your library. You may play it this turn.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Charred Foyer // Warped Space

Reckless Impulse

Valakut Exploration

Landfall — Whenever a land you control enters, exile the top card of your library. You may play that card for as long as it remains exiled.
At the beginning of your end step, if there are cards exiled with this enchantment, put them into their owner's graveyard, then this enchantment deals that much damage to each opponent.

Makindi Sliderunner

Trample
Landfall — Whenever a land you control enters, this creature gets +1/+1 until end of turn.

Anger

Haste
As long as this card is in your graveyard and you control a Mountain, creatures you control have haste.