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.)

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Mana Geyser

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

Dragonlord's Servant

Dragon 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.

Command Tower

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

Pirate's Pillage

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 artifact: Add one mana of any color.")

Fire Diamond

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

Seething Song

Unexpected Windfall

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Mountain

Dragon's Fire

As an additional cost to cast this spell, you may reveal a Dragon card from your hand or choose a Dragon you control.
Dragon's Fire deals 3 damage to target creature or planeswalker. If you revealed a Dragon card or chose a Dragon as you cast this spell, Dragon's Fire deals damage equal to the power of that card or creature instead.

Carnelian Orb of Dragonkind

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

Acolyte of Bahamut

Commander creatures you own have "The first Dragon spell you cast each turn costs {2} less to cast."

Arcane Signet

Tiamat's Fanatics

Haste
Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Dragon Egg

Defender
When Dragon Egg dies, create a 2/2 red Dragon creature token with flying and "{R}: This creature gets +1/+0 until end of turn."