Definite 

Thrill of Possibility

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

big gets

Claws of Valakut

Enchant creature
Enchanted creature gets +1/+0 for each Mountain you control and has first strike.

unsure/have 

Stonefury

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

unsure/dont hav

Sulfurous Blast

Sulfurous Blast deals 2 damage to each creature and each player. If you cast this spell during your main phase, Sulfurous Blast deals 3 damage to each creature and each player instead.

Getting

Earthquake

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

Filler 

Pilgrim's Eye

Flying
When Pilgrim's Eye enters the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Reverberate

Copy target instant or sorcery spell. You may choose new targets for the copy.

deffo dragons 

Hoard-Smelter Dragon

Flying
{3}{R}: Destroy target artifact. Hoard-Smelter Dragon gets +X/+0 until end of turn, where X is that artifact's mana value.

Fire Prophecy

Fire Prophecy deals 3 damage to target creature. You may put a card from your hand on the bottom of your library. If you do, draw a card.

Akoum Hellkite

Flying
Landfall — Whenever a land enters the battlefield under your control, Akoum Hellkite deals 1 damage to any target. If that land is a Mountain, Akoum Hellkite deals 2 damage instead.

Have

Bogardan Hellkite

Flash
Flying
When Bogardan Hellkite enters the battlefield, it deals 5 damage divided as you choose among any number of targets.

Fire Diamond

Fire Diamond enters the battlefield tapped.
{T}: Add {R}.

maybe to get 

Draconic Roar

As an additional cost to cast this spell, you may reveal a Dragon card from your hand.
Draconic Roar deals 3 damage to target creature. If you revealed a Dragon card or controlled a Dragon as you cast this spell, Draconic Roar deals 3 damage to that creature's controller.

Thud

As an additional cost to cast this spell, sacrifice a creature.
Thud deals damage equal to the sacrificed creature's power to any target.

Bolt Bend

This spell costs {3} less to cast if you control a creature with power 4 or greater.
Change the target of target spell or ability with a single target.

Seer's Lantern

{T}: Add {C}.
{2}, {T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Maybe to addd

Blastfire Bolt

Blastfire Bolt deals 5 damage to target creature. Destroy all Equipment attached to that creature.

Chandra's Pyreling

Whenever a source you control deals noncombat damage to an opponent, Chandra's Pyreling gets +1/+0 and gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

Roar of the Crowd

Choose a creature type. Roar of the Crowd deals damage to any target equal to the number of permanents you control of the chosen type.

Furyborn Hellkite

Bloodthirst 6 (If an opponent was dealt damage this turn, this creature enters the battlefield with six +1/+1 counters on it.)
Flying

Dragonspeaker Shaman

Dragon spells you cast cost {2} less to cast.

Archetype of Aggression

Creatures you control have trample.
Creatures your opponents control lose trample and can't have or gain trample.

Granite Grip

Enchant creature
Enchanted creature gets +1/+0 for each Mountain you control.

Tin Street Market

Enchant land
Enchanted land has "{T}, Discard a card: Draw a card."

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Fervor

Creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Blazing Volley

Blazing Volley deals 1 damage to each creature your opponents control.

Ruthless Invasion

({R/P} can be paid with either {R} or 2 life.)
Nonartifact creatures can't block this turn.

Rumbling Rockslide

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

Rite of Flame

Add {R}{R}, then add {R} for each card named Rite of Flame in each graveyard.

Alena, Kessig Trapper

First strike
{T}: Add an amount of {R} equal to the greatest power among creatures you control that entered the battlefield this turn.
Partner (You can have two commanders if both have partner.)

Seismic Strike

Seismic Strike deals damage to target creature equal to the number of Mountains you control.

Thran Dynamo

Spectral Searchlight

{T}: Choose a player. That player adds one mana of any color they choose.

Scorching Dragonfire

Scorching Dragonfire deals 3 damage to target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.

Court of Ire

When Court of Ire enters the battlefield, you become the monarch.
At the beginning of your upkeep, Court of Ire deals 2 damage to any target. If you're the monarch, it deals 7 damage instead.

Sarkhan, Dragonsoul

+2: Sarkhan, Dragonsoul deals 1 damage to each opponent and each creature your opponents control.
−3: Sarkhan, Dragonsoul deals 4 damage to target player or planeswalker.
−9: Search your library for any number of Dragon creature cards, put them onto the battlefield, then shuffle.

Belbe's Portal

As Belbe's Portal enters the battlefield, choose a creature type.
{3}, {T}: You may put a creature card of the chosen type from your hand onto the battlefield.

Mordant Dragon

Flying
{1}{R}: Mordant Dragon gets +1/+0 until end of turn.
Whenever Mordant Dragon deals combat damage to a player, you may have it deal that much damage to target creature that player controls.

Coordinated Assault

Up to two target creatures each get +1/+0 and gain first strike until end of turn.

Burning Anger

Enchant creature
Enchanted creature has "{T}: This creature deals damage equal to its power to any target."

Magmaquake

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

Shatter

Terror of Mount Velus

Flying, double strike
When Terror of Mount Velus enters the battlefield, creatures you control gain double strike until end of turn.

Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Archwing Dragon

Flying, haste
At the beginning of the end step, return Archwing Dragon to its owner's hand.

Shivan Meteor

Shivan Meteor deals 13 damage to target creature.
Suspend 2—{1}{R}{R} (Rather than cast this card from your hand, you may pay {1}{R}{R} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Dragonstorm

Search your library for a Dragon permanent card, put it onto the battlefield, then shuffle.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Mountain

Geosurge

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

Seething Song

Armillary Sphere

{2}, {T}, Sacrifice Armillary Sphere: Search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.

Spit Flame

Spit Flame deals 4 damage to target creature.
Whenever a Dragon enters the battlefield under your control, you may pay {R}. If you do, return Spit Flame from your graveyard to your hand.

Tormenting Voice

Raking Claws

Target creature gains double strike until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Lathliss, Dragon Queen

Flying
Whenever another nontoken Dragon enters the battlefield under your control, create a 5/5 red Dragon creature token with flying.
{1}{R}: Dragons you control get +1/+0 until end of turn.

Thundermaw Hellkite

Flying
Haste (This creature can attack and {T} as soon as it comes under your control.)
When Thundermaw Hellkite enters the battlefield, it deals 1 damage to each creature with flying your opponents control. Tap those creatures.

Hammer of Purphoros

Creatures you control have haste.
{2}{R}, {T}, Sacrifice a land: Create a 3/3 colorless Golem enchantment artifact creature token.

Don't Have

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 Fallout

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

Arcane Signet

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

Opportunistic Dragon

Flying
When Opportunistic Dragon enters the battlefield, choose target Human or artifact an opponent controls. For as long as Opportunistic Dragon remains on the battlefield, gain control of that permanent, it loses all abilities, and it can't attack or block.

Sol Ring

Mana Geyser

Add {R} for each tapped land your opponents control.

Jalum Tome

{2}, {T}: Draw a card, then discard a card.

Shredded Sails

Choose one —
• Destroy target artifact.
• Shredded Sails deals 4 damage to target creature with flying.
Cycling {2} ({2}, Discard this card: Draw a card.)

By Force

Horizon Stone

If you would lose unspent mana, that mana becomes colorless instead.

Hazoret's Monument

Red creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, you may discard a card. If you do, draw a card.

Sarkhan's Triumph

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

Rummaging Goblin

Vow of Lightning

Enchant creature
Enchanted creature gets +2/+2, has first strike, and can't attack you or planeswalkers you control.

Haunted Cloak

Equipped creature has vigilance, trample, and haste.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Soul's Fire

Target creature you control deals damage equal to its power to any target.

Molten Echoes

As Molten Echoes enters the battlefield, choose a creature type.
Whenever a nontoken creature of the chosen type enters the battlefield under your control, create a token that's a copy of that creature. That token gains haste. Exile it at the beginning of the next end step.

Dragon Hatchling

Flying
{R}: Dragon Hatchling gets +1/+0 until end of turn.

Heightened Reflexes

Target creature gets +1/+0 until end of turn. Put a first strike counter on it.

Firebreathing

Enchant creature
{R}: Enchanted creature gets +1/+0 until end of turn.

Dragon Tempest

Whenever a creature with flying enters the battlefield under your control, it gains haste until end of turn.
Whenever a Dragon enters the battlefield under your control, it deals X damage to any target, where X is the number of Dragons you control.

Mind Stone

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

Mana Flare

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Dragon Mage

Flying
Whenever Dragon Mage deals combat damage to a player, each player discards their hand, then draws seven cards.

Dragon's Hoard

Whenever a Dragon enters the battlefield under your control, put a gold counter on Dragon's Hoard.
{T}, Remove a gold counter from Dragon's Hoard: Draw a card.
{T}: Add one mana of any color.

Spawn of Thraxes

Flying
When Spawn of Thraxes enters the battlefield, it deals damage to any target equal to the number of Mountains you control.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Volcanic Geyser

Volcanic Geyser deals X damage to any target.

Dragon's Claw

Whenever a player casts a red spell, you may gain 1 life.

Turn to Slag

Turn to Slag deals 5 damage to target creature. Destroy all Equipment attached to that creature.

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Sarkhan the Masterless

Whenever a creature attacks you or a planeswalker you control, each Dragon you control deals 1 damage to that creature.
+1: Until end of turn, each planeswalker you control becomes a 4/4 red Dragon creature and gains flying.
−3: Create a 4/4 red Dragon creature token with flying.

Traitorous Blood

Gain control of target creature until end of turn. Untap it. It gains trample and haste until end of turn.

Rack and Ruin

Utvara Hellkite

Flying
Whenever a Dragon you control attacks, create a 6/6 red Dragon creature token with flying.

Demoralize

All creatures gain menace until end of turn. (They can't be blocked except by two or more creatures.)
Threshold — If seven or more cards are in your graveyard, creatures can't block this turn.

Sparktongue Dragon

Flying
When Sparktongue Dragon enters the battlefield, you may pay {2}{R}. When you do, it deals 3 damage to any target.

Myriad Landscape

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

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Undying Rage

Enchant creature
Enchanted creature gets +2/+2 and can't block.
When Undying Rage is put into a graveyard from the battlefield, return Undying Rage to its owner's hand.

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.