Chaos Dragon

Flying, haste
This creature attacks each combat if able.
At the beginning of combat on your turn, each player rolls a d20. If one or more opponents had the highest result, this creature can't attack those players or planeswalkers they control this combat.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Dragonlord's Servant

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

Drakuseth, Maw of Flames

Flying
Whenever Drakuseth attacks, it deals 4 damage to any target and 3 damage to each of up to two other targets.

Savage Ventmaw

Flying
Whenever this creature attacks, add {R}{R}{R}{G}{G}{G}. Until end of turn, you don't lose this mana as steps and phases end.

Dissonant Wave

Counter target activated or triggered ability from a noncreature source. (Then exile this card. You may cast the creature later from exile.)

Emerald Dragon

Emerald Dragon // Dissonant Wave

Archive Dragon

Flying
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When this creature enters, scry 2.

Dragon's Hoard

Whenever a Dragon you control enters, put a gold counter on this artifact.
{T}, Remove a gold counter from this artifact: Draw a card.
{T}: Add one mana of any color.

Thunder Dragon

Flying
When this creature enters, it deals 3 damage to each creature without flying.

Atarka, World Render

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

Renari, Merchant of Marvels

You may cast Dragon spells and artifact spells as though they had flash.
Choose a Background (You can have a Background as a second commander.)

Reckless Barbarian

Korlessa, Scale Singer

You may look at the top card of your library any time.
You may cast Dragon spells from the top of your library.

Have

Lozhan, Dragons' Legacy

Flying
Whenever you cast an Adventure or Dragon spell, Lozhan deals damage equal to that spell's mana value to any target that isn't a commander.

Thrakkus the Butcher

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

Patron of the Arts

When this creature enters or dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Goldspan Dragon

Flying, haste
Whenever this creature attacks or becomes the target of a spell, create a Treasure token.
Treasures you control have "{T}, Sacrifice this artifact: Add two mana of any one color."

Draconic Muralists

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

Miirym, Sentinel Wyrm

Flying, ward {2}
Whenever another nontoken Dragon you control enters, create a token that's a copy of it, except the token isn't legendary.

Bathe in Gold

Create a Treasure token. (Then exile this card. You may cast the creature later from exile.)

Young Red Dragon

Young Red Dragon // Bathe in Gold

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.)

Scaled Nurturer

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

Dragonspeaker Shaman

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

Cultivate

Astral Dragon

Flying
Project Image — When this creature enters, create two tokens that are copies of target noncreature permanent, except they're 3/3 Dragon creatures in addition to their other types, and they have flying.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Wrathful Red Dragon

Flying
Whenever a Dragon you control is dealt damage, it deals that much damage to any target that isn't a Dragon.

Acolyte of Bahamut

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

Garruk's Uprising

When this enchantment enters, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever a creature you control with power 4 or greater enters, draw a card.

Feywild Visitor

Commander creatures you own have "Whenever one or more nontoken creatures you control deal combat damage to a player, you create a 1/1 blue Faerie Dragon creature token with flying."

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.

Forktail Sweep

Forktail Sweep deals 1 damage to each creature you don't control. (Then exile this card. You may cast the creature later from exile.)

Fang Dragon

Fang Dragon // Forktail Sweep

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.

Draconic Lore

This spell costs {2} less to cast if you control a Dragon.
Draw three cards.

Earthquake Dragon

This spell costs {X} less to cast, where X is the total mana value of Dragons you control.
Flying, trample
{2}{G}, Sacrifice a land: Return this card from your graveyard to your hand.

Firkraag, Cunning Instigator

Flying, haste
Whenever one or more Dragons you control attack an opponent, goad target creature that player controls.
Whenever a creature deals combat damage to one of your opponents, if that creature had to attack this combat, you put a +1/+1 counter on Firkraag and you draw a card.

Carnelian Orb of Dragonkind

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