Dragon Tribal Synergies with Tiamat (EDH / Commander)

A casual EDH dragon tribal deck with an infinite combo (Hellkite Charger + Old Gnawbone) and a fun combo (Morophon, the Boundless + Jodah, Archmage Eternal). Instead of just playing big beaters quickly, I prefer to use cards that synergize well with each other, which you can see especially well in my choice of dragons in this deck. While this is by no means a cEDH deck, I am trying to make it suitable for competition in higher tier casual pods. Any recommendations to accomplish that, aside from obvious things like: more fetches, more shocks, and/or more ABU duals, would be greatly appreciated. To elaborate: I know there are cards that would improve this deck AND fit well with what I want to do with this deck. However, the cards I know of are cards like Smothering Tithe, Rhystic Study, Mana Crypt, and the aforementioned lands, only a couple of which I would consider adding gradually due to $$$ concerns. So any other tips would be appreciated.

> Combo 1: Morophon, the Boundless + Jodah, Archmage Eternal:

Result: You can cast Dragon creature spells for free.

Requires: All permanents on the battlefield.

Steps:

• Cast Morophon, the Boundless, choosing dragon as your creature type
• Cast Jodah, Archmage Eternal

> Combo 2: Hellkite Charger + Old Gnawbone:

Result: Infinite combat phases. Infinite combat damage. Infinite Treasure tokens. Infinite colored mana.

Requires: All permanents on the battlefield. Old Gnawbone does not have summoning sickness. Hellkite Charger does not have summoning sickness. An opponent can not block Old Gnawbone. An opponent can not block Hellkite Charger. 5RR available.

Steps:

• Declare Hellkite Charger and Old Gnawbone as attacker.
• Hellkite Charger triggers, pay 5RR to untap all attacking creatures and to get an additional combat phase after this one.
• Old Gnawbone triggers for each creature that dealt combat damage, creating a number of treasures equal to the damage dealt with each trigger.
• activate seven Treasure tokens by tapping and sacrificing them, adding 5RR.
• Repeat