Crucible of the Spirit Dragon

{T}: Add {C}.
{1}, {T}: Put a storage counter on Crucible of the Spirit Dragon.
{T}, Remove X storage counters from Crucible of the Spirit Dragon: Add X mana in any combination of colors. Spend this mana only to cast Dragon spells or activate abilities of Dragons.

Sarkhan, Fireblood

+1: You may discard a card. If you do, draw a card.
+1: Add two mana in any combination of colors. Spend this mana only to cast Dragon spells.
−7: Create four 5/5 red Dragon creature tokens with flying.

Vial of Dragonfire

{2}, {T}, Sacrifice Vial of Dragonfire: It deals 2 damage to target creature.

Dragonloft Idol

As long as you control a Dragon, Dragonloft Idol gets +1/+1 and has flying and trample.

Herdchaser Dragon

Flying, trample
Megamorph {5}{G}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Herdchaser Dragon is turned face up, put a +1/+1 counter on each other Dragon creature you control.

Dragon's Hoard

Whenever a Dragon you control enters, 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.

Descent of the Dragons

Destroy any number of target creatures. For each creature destroyed this way, its controller creates a 4/4 red Dragon creature token with flying.

Ancient Copper Dragon

Flying
Whenever Ancient Copper Dragon deals combat damage to a player, roll a d20. You create a number of Treasure tokens equal to the result.

Arcane Signet

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

Dragonlord's Servant

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

Diamond Pick-Axe

Indestructible (Effects that say "destroy" don't destroy this artifact.)
Equipped creature gets +1/+1 and has "Whenever this creature attacks, create a Treasure token." (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Equip {2}

Dragonspeaker Shaman

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

Ganax, Astral Hunter

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

Temple of the Dragon Queen

As Temple of the Dragon Queen enters, you may reveal a Dragon card from your hand. Temple of the Dragon Queen enters tapped unless you revealed a Dragon card this way or you control a Dragon.
As Temple of the Dragon Queen enters, choose a color.
{T}: Add one mana of the chosen color.

Mind Stone

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

Scaleguard Sentinels

As an additional cost to cast this spell, you may reveal a Dragon card from your hand.
Scaleguard Sentinels enters with a +1/+1 counter on it if you revealed a Dragon card or controlled a Dragon as you cast this spell.

Dragonmaster Outcast

At the beginning of your upkeep, if you control six or more lands, create a 5/5 red Dragon creature token with flying.

Scaled Nurturer

{T}: Add {G}. When you spend this mana to cast a Dragon creature spell, you gain 2 life.

Draconic Muralists

When Draconic Muralists dies, you may search your library for a Dragon card, reveal it, put it into your hand, then shuffle.

Sarkhan's Triumph

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

Sarkhan Vol

+1: Creatures you control get +1/+1 and gain haste until end of turn.
−2: Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.
−6: Create five 4/4 red Dragon creature tokens with flying.

Dragon Tempest

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

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.

Thrakkus the Butcher

Trample
Whenever Thrakkus the Butcher attacks, double the power of each Dragon you control until end of turn.

Guild Artisan

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, you create two Treasure tokens." (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Crucible of Fire

Green Dragon

Flying
Poison Breath — When Green Dragon enters, until end of turn, whenever a creature an opponent controls is dealt damage, destroy it.

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.

Sol Ring

Breath Weapon

Breath Weapon deals 2 damage to each non-Dragon creature.

Ancient Bronze Dragon

Flying
Whenever Ancient Bronze Dragon deals combat damage to a player, roll a d20. When you do, put X +1/+1 counters on each of up to two target creatures, where X is the result.

Draconic Intervention

As an additional cost to cast this spell, exile an instant or sorcery card from your graveyard.
Draconic Intervention deals X damage to each non-Dragon creature, where X is the exiled card's mana value. If a creature dealt damage this way would die this turn, exile it instead.
Exile Draconic Intervention.

Atarka, World Render

Flying, trample
Whenever a Dragon you control attacks, it gains double strike until end of turn.

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.)

Jade Orb of Dragonkind

{T}: Add {G}. When you spend this mana to cast a Dragon creature spell, it enters with an additional +1/+1 counter on it and gains hexproof until your next turn. (It can't be the target of spells or abilities your opponents control.)

Dragon Broodmother

Flying
At the beginning of each upkeep, create a 1/1 red and green Dragon creature token with flying and devour 2. (As the token enters, you may sacrifice any number of creatures. It enters with twice that many +1/+1 counters on it.)

Carnelian Orb of Dragonkind

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