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.)

Dragonlord's Servant

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

Elvish Pioneer

When this creature enters, you may put a basic land card from your hand onto the battlefield tapped.

Arcane Signet

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

Sol Ring

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.

Elvish Mystic

Fellwar Stone

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

Reckless Barbarian

Goblin Anarchomancer

Each spell you cast that's red or green costs {1} less to cast.

Acolyte of Bahamut

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

Walking Atlas

{T}: You may put a land card from your hand onto the battlefield.

Mind Stone

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

Arboreal Grazer

Reach
When this creature enters, you may put a land card from your hand onto the battlefield tapped.

Up the Beanstalk

When this enchantment enters and whenever you cast a spell with mana value 5 or greater, draw a card.

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.

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.

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.

Llanowar Elves

Colossal Majesty

At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.