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."

Vengeful Ancestor

Flying
Whenever this creature enters or attacks, goad target creature. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)
Whenever a goaded creature attacks, it deals 1 damage to its controller.

Verix Bladewing

Kicker {3} (You may pay an additional {3} as you cast this spell.)
Flying
When Verix enters, if it was kicked, create Karox Bladewing, a legendary 4/4 red Dragon creature token with flying.

Sol Ring

Furnace Whelp

Flying
{R}: This creature gets +1/+0 until end of turn.

Ruby Medallion

Red spells you cast cost {1} less to cast.

Thrill of Possibility

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

Skyship Stalker

Flying
{R}: This creature gets +1/+0 until end of turn.
{R}: This creature gains first strike until end of turn.
{R}: This creature gains haste until end of turn.

Swashbuckler Extraordinaire

When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Whenever you attack, you may sacrifice one or more Treasures. When you do, up to that many target creatures gain double strike until end of turn.

Ganax, Astral Hunter

Flying
Whenever Ganax or another Dragon you control enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Choose a Background (You can have a Background as a second commander.)

Dragonspeaker Shaman

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

Three Tree Mascot

Changeling (This card is every creature type.)
{1}: Add one mana of any color. Activate only once each turn.

Fire-Belly Changeling

Changeling (This card is every creature type.)
{R}: This creature gets +1/+0 until end of turn. Activate no more than twice each turn.

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.

Curse of Opulence

Enchant player
Whenever enchanted player is attacked, create a Gold token. Each opponent attacking that player does the same. (A Gold token is an artifact with "Sacrifice this token: Add one mana of any color.")

Firespitter Whelp

Flying
Whenever you cast a noncreature or Dragon spell, this creature deals 1 damage to each opponent.

Fellwar Stone

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

Rapacious Dragon

Flying
When this creature enters, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Dragon Mage

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

Dragonhawk, Fate's Tempest

Flying
Whenever Dragonhawk enters or attacks, exile the top X cards of your library, where X is the number of creatures you control with power 4 or greater. You may play those cards until your next end step. At the beginning of your next end step, Dragonhawk deals 2 damage to each opponent for each of those cards that are still exiled.

Fledgling Dragon

Flying
Threshold — As long as seven or more cards are in your graveyard, this creature gets +3/+3 and has "{R}: This creature gets +1/+0 until end of turn."

Worn Powerstone

This artifact enters tapped.
{T}: Add {C}{C}.

Mountain

Territorial Hellkite

Flying, haste
At the beginning of combat on your turn, choose an opponent at random that this creature didn't attack during your last combat. This creature attacks that player this combat if able. If you can't choose an opponent this way, tap this creature.

Myr Convert

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
{T}, Pay 2 life: Add one mana of any color.

Furious Rise

At the beginning of your end step, if you control a creature with power 4 or greater, exile the top card of your library. You may play that card until you exile another card with this enchantment.

Dragon Hatchling

Crucible of Fire

Opportunistic Dragon

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

Demanding Dragon

Flying
When this creature enters, it deals 5 damage to target opponent unless that player sacrifices a creature of their choice.

Wild Guess

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.

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.

Dragonlord's Servant

Dragon spells you cast cost {1} less to cast.

Scourge of the Throne

Flying
Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Whenever this creature attacks for the first time each turn, if it's attacking the player with the most life or tied for most life, untap all attacking creatures. After this phase, there is an additional combat phase.

Ilharg, the Raze-Boar

Trample
Whenever Ilharg attacks, you may put a creature card from your hand onto the battlefield tapped and attacking. Return that creature to your hand at the beginning of the next end step.
When Ilharg dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Rising of the Day

Creatures you control have haste.
Legendary creatures you control get +1/+0.

Thunderbreak Regent

Flying
Whenever a Dragon you control becomes the target of a spell or ability an opponent controls, this creature deals 3 damage to that player.

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Unexpected Windfall

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Arcane Signet

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

Lathliss, Dragon Queen

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

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.")

Fiery Annihilation

Fiery Annihilation deals 5 damage to target creature. Exile up to one target Equipment attached to that creature. If that creature would die this turn, exile it instead.

Season of the Bold

Choose up to five {P} worth of modes. You may choose the same mode more than once.
{P} — Create a tapped Treasure token.
{P}{P} — Exile the top two cards of your library. Until the end of your next turn, you may play them.
{P}{P}{P} — Until the end of your next turn, whenever you cast a spell, Season of the Bold deals 2 damage to up to one target creature.

Barkform Harvester

Changeling (This card is every creature type.)
Reach
{2}: Put target card from your graveyard on the bottom of your library.

Archwing Dragon

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

Simian Spirit Guide

Kolaghan Warmonger

Haste
Whenever this creature attacks, look at the top six cards of your library. You may reveal a Dragon card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Bloodline Pretender

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
Whenever another creature you control of the chosen type enters, put a +1/+1 counter on this creature.

Sarkhan's Triumph

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

Taurean Mauler

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Wayfarer's Bauble

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

Fractured Powerstone

{T}: Add {C}.
{T}: Roll the planar die. Activate only as a sorcery.

Carnelian Orb of Dragonkind

{T}: Add {R}. If that mana is spent on a Dragon creature spell, it gains haste until end of turn.

Big Score

Basalt Monolith

This artifact doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap this artifact.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Earthquake

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

Dragon Whelp

Flying
{R}: This creature gets +1/+0 until end of turn. If this ability has been activated four or more times this turn, sacrifice this creature at the beginning of the next end step.

Rakdos Pit Dragon

{R}{R}: This creature gains flying until end of turn.
{R}: This creature gets +1/+0 until end of turn.
Hellbent — This creature has double strike as long as you have no cards in hand.

Wild Magic Surge

Destroy target permanent an opponent controls. Its controller reveals cards from the top of their library until they reveal a permanent card that shares a card type with that permanent. They put that card onto the battlefield and the rest on the bottom of their library in a random order.

Sneak Attack

{R}: You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice the creature at the beginning of the next end step.

Magmaquake

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

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)