Vriaeliss,
Here's a few thoughts ...

• It's a little janky, but maybe Enlightened Tutor or Hoarding Dragon to get your Dragon Arch?
  
• Maybe a Dragonmaster Outcast? He doesn't make it around the table that often, but even when he doesn't, I figure making someone trade quality removal for a 1-mana 1/1 is still good value.
  
• They're totally off-flavor, but if you find Marath wants a few more +1/+1 counters, maybe something like Bloodspore Thrinax, Cathars' Crusade, or Forgotten Ancient?
  
• If you haven't already, you might also look at Artifact Mutation and Aura Mutation. I like them better than Fate Forgotten and even Hull Breach.

Those are some great suggestions! Thank you very much for taking the time to offer them :)

I like the combination potential of Bloodspore Thrinax with either Mutation spell. I may not lose Fate Forgotten, since I run into a fair amount of indestructible artifacts my group likes to play, or playing decks that can easily return or abuse Eldrazi from the graveyard.

Dragonmaster Outcast definitely on my list of cards to get. Hoarding Dragon is an excellent suggestion as well, fits the theme and super useful.

Utvara Hellkite forever.

Are you sure that Mayael the Anima wouldn't be a better commander for what you're trying to do?

In some ways she'd be better, yeah. Marath helps acting as some chump removal/direct damage, chump-blocker generation, and to bolster my dragons. Marath will be much more potent when I get my Cathars' Crusade for this deck and when it's pulled too. Make all my dragons better for (and no net loss of counters on Marath)? I'll take it :) Hell, Marath would get stronger if I also had Hardened Scales in play. Or if I ever make myself put my Doubling Season in this deck.

That said, Mayael might be good add to the deck anyway. Supplement the Dragon Arch in case I can't fetch it or draw it.

I think you could take out all your instants except for Sarkhan's TriumphAlso add cards like Lightning Bolt and Swords to Plowshares and Path to ExileAnd if you want tribal dragons add Crucible of Fire, Coat of Arms, and Obelisk of UrdYour commander should be Rith, the Awakener

I could do without a few of the instants, yeah. I wouldn't remove all of them though. Crucible of Fire is a good pickup. Condsidered Obelisk of Urd, just need to obtain one.

I don't know how much I like Rith as commander. Marath is fast, strong, and flexible, I really like being able to rely on all three aspects of her. I should definitely add Rith though.