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.)

As this artifact enters, choose a creature type. Creature spells of the chosen type cost {2} less to cast.

Dragon creatures you control get +3/+3.

Equipped creature has myriad. (Whenever it 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.) Equip {4}

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.) Whenever equipped creature attacks, put a +1/+1 counter on each creature you control. If you have the city's blessing, put two +1/+1 counters on each creature you control instead. Equip {3}

As this artifact enters, choose a creature type. Creatures you control of the chosen type get +1/+1. Whenever you cast a creature spell of the chosen type, draw a card.

As Three Tree City enters, choose a creature type. {T}: Add {C}. {2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.