Geosurge

Add {R}{R}{R}{R}{R}{R}{R}. Spend this mana only to cast artifact or creature spells.

Tunneling Geopede

Landfall — Whenever a land enters the battlefield under your control, Tunneling Geopede deals 1 damage to each opponent.

Lava Burst

Lava Burst deals X damage to any target. If Lava Burst would deal damage to a creature, that damage can't be prevented or dealt instead to another permanent or player.

Dormant Volcano

Dormant Volcano enters the battlefield tapped.
When Dormant Volcano enters the battlefield, sacrifice it unless you return an untapped Mountain you control to its owner's hand.
{T}: Add {C}{R}.

Geode Rager

First strike
Landfall — Whenever a land enters the battlefield under your control, goad each creature target player controls. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Geomancer's Gambit

Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.
Draw a card.

Volcano Hellion

Volcano Hellion has echo {X}, where X is your life total. (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Volcano Hellion enters the battlefield, it deals an amount of damage of your choice to you and target creature. The damage can't be prevented.

Pyroclastic Hellion

When Pyroclastic Hellion enters the battlefield, you may return a land you control to its owner's hand. When you do, Pyroclastic Hellion deals 2 damage to each opponent.

Tectonic Break

Quakebringer

Your opponents can't gain life.
At the beginning of your upkeep, Quakebringer deals 2 damage to each opponent. This ability triggers only if Quakebringer is on the battlefield or if Quakebringer is in your graveyard and you control a Giant.
Foretell {2}{R}{R}

Tectonic Instability

Whenever a land enters the battlefield, tap all lands its controller controls.

Lava Runner

Haste
Whenever Lava Runner becomes the target of a spell or ability, that spell or ability's controller sacrifices a land.

Mana Geode

When Mana Geode enters the battlefield, scry 1.
{T}: Add one mana of any color.

Island

Smoldering Crater

Smoldering Crater enters the battlefield tapped.
{T}: Add {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Geode Golem

Trample
Whenever Geode Golem deals combat damage to a player, you may cast your commander from the command zone without paying its mana cost. (You still pay any additional costs.)

Valakut, the Molten Pinnacle

Valakut, the Molten Pinnacle enters the battlefield tapped.
Whenever a Mountain enters the battlefield under your control, if you control at least five other Mountains, you may have Valakut, the Molten Pinnacle deal 3 damage to any target.
{T}: Add {R}.

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.

Tectonic Giant

Whenever Tectonic Giant attacks or becomes the target of a spell an opponent controls, choose one —
• Tectonic Giant deals 3 damage to each opponent.
• Exile the top two cards of your library. Choose one of them. Until the end of your next turn, you may play that card.

Volcanic Submersion

Destroy target artifact or land.
Cycling {2} ({2}, Discard this card: Draw a card.)

Magmasaur

Magmasaur enters the battlefield with five +1/+1 counters on it.
At the beginning of your upkeep, you may remove a +1/+1 counter from Magmasaur. If you don't, sacrifice Magmasaur and it deals damage equal to the number of +1/+1 counters on it to each creature without flying and each player.

Magma Pummeler

Magma Pummeler enters the battlefield with X +1/+1 counters on it.
If damage would be dealt to Magma Pummeler while it has a +1/+1 counter on it, prevent that damage and remove that many +1/+1 counters from it. When one or more counters are removed from Magma Pummeler this way, it deals that much damage to any target.

Magmatic Insight

As an additional cost to cast this spell, discard a land card.
Draw two cards.

Volcanic Spray

Volcanic Spray deals 1 damage to each creature without flying and each player.
Flashback {1}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Tectonic Hellion

Haste
Whenever Tectonic Hellion attacks, each player who controls the most lands sacrifices two lands.

Earth Rift

Destroy target land.
Flashback {5}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Crater Hellion

Echo {4}{R}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Crater Hellion enters the battlefield, it deals 4 damage to each other creature.

Fault Line

Fault Line deals X damage to each creature without flying and each player.

Geological Appraiser

When Geological Appraiser enters the battlefield, if you cast it, discover 3. (Exile cards from the top of your library until you exile a nonland card with mana value 3 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.)

Rockslide Elemental

First strike
Whenever another creature dies, you may put a +1/+1 counter on Rockslide Elemental.

Canyon Jerboa

Landfall — Whenever a land enters the battlefield under your control, creatures you control get +1/+1 until end of turn.

Volcanic Upheaval

Plated Geopede

First strike
Landfall — Whenever a land enters the battlefield under your control, Plated Geopede gets +2/+2 until end of turn.

Magmaquake

Magmaquake deals X damage to each creature without flying and each planeswalker.

Rolling Earthquake

Rolling Earthquake deals X damage to each creature without horsemanship and each player.

Rockslide Ambush

Rockslide Ambush deals damage to target creature equal to the number of Mountains you control.

Tectonic Edge

{T}: Add {C}.
{1}, {T}, Sacrifice Tectonic Edge: Destroy target nonbasic land. Activate only if an opponent controls four or more lands.

Tectonic Rift

Destroy target land. Creatures without flying can't block this turn.

Seismic Wave

Seismic Wave deals 2 damage to any target and 1 damage to each nonartifact creature target opponent controls.

Caldera Hellion

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.)
When Caldera Hellion enters the battlefield, it deals 3 damage to each creature.

Geothermal Crevice

Geothermal Crevice enters the battlefield tapped.
{T}: Add {R}.
{T}, Sacrifice Geothermal Crevice: Add {B}{G}.

Rumbling Rockslide

Rumbling Rockslide deals damage to target creature equal to the number of lands you control.

Volcanic Rambler

{2}{R}: Volcanic Rambler deals 1 damage to target player or planeswalker.

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. Shivan Reef deals 1 damage to you.

Molten Monstrosity

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
Trample

Island Fish Jasconius

Island Fish Jasconius doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {U}{U}{U}. If you do, untap Island Fish Jasconius.
Island Fish Jasconius can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Island Fish Jasconius.

Magma Hellion

Assist (Another player can pay up to {6} of this spell's cost.)
Trample, haste

Mine Collapse

If it's your turn, you may sacrifice a Mountain rather than pay this spell's mana cost.
Mine Collapse deals 5 damage to target creature or planeswalker.

Seismic Elemental

When Seismic Elemental enters the battlefield, creatures without flying can't block this turn.

Geology Enthusiast

At the beginning of your end step, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")
{6}: Draw a card and put a +1/+1 counter on Geology Enthusiast.

Flood

{U}{U}: Tap target creature without flying.

Earthquake

Earthquake deals X damage to each creature without flying and each player.

Winding Canyons

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

Faultgrinder

Trample
When Faultgrinder enters the battlefield, destroy target land.
Evoke {4}{R} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Rumbling Aftershocks

Whenever you cast a kicked spell, you may have Rumbling Aftershocks deal damage to any target equal to the number of times that spell was kicked.

Molten Tributary

({T}: Add {U} or {R}.)
Molten Tributary enters the battlefield tapped.

Volcanic Awakening

Destroy target land.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Glaciers

At the beginning of your upkeep, sacrifice Glaciers unless you pay {W}{U}.
All Mountains are Plains.

Fault Riders

Sacrifice a land: Fault Riders gets +2/+0 and gains first strike until end of turn. Activate only once each turn.

Terminal Moraine

{T}: Add {C}.
{2}, {T}, Sacrifice Terminal Moraine: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Mountain

Volcanic Fallout

This spell can't be countered.
Volcanic Fallout deals 2 damage to each creature and each player.

Urborg Volcano

Urborg Volcano enters the battlefield tapped.
{T}: Add {B} or {R}.

Lava Blister

Destroy target nonbasic land unless its controller has Lava Blister deal 6 damage to them.

Cenote Scout

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.)

Plains

Skyclave Geopede

Trample
Landfall — Whenever a land enters the battlefield under your control, Skyclave Geopede gets +2/+2 until end of turn.

Rocky Tar Pit

Rocky Tar Pit enters the battlefield tapped.
{T}, Sacrifice Rocky Tar Pit: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.