I'm not sure if this is a casual deck or if your play group is okay with it, but
Primeval Titan is banned in commander. Also,
Rattleclaw Mystic is not legal for this deck since it has a blue mana symbol on it.
Oracle of Mul Daya and
Azusa, Lost but Seeking would be great in this deck. (Looking at what's in here I don't think price is an issue?)
Walking Atlas would be great-a 1/1 won't stay on the battlefield for long, but his tap ability works for non-basics and is at instant speed. The instant speed will be useful when you need your landfall creatures for blockers. Autarka's Command is a fantastic card that can do the same thing.
Horn of Greed would also be a good way to refill your hand, especially if you add more play additional land cards like
Exploration or
Burgeoning. I'm not a huge fan of group hug cards in general, but I could picture this deck just spitting out lands and being stagnant after you've exhausted them. You might want to look into some removal too. I think
Turntimber Basilisk was the only removal-like spell/creature in the deck??? Red has tons of answers for lands and artifacts, and green for artifacts and enchantments. I'm rather fond of
Return to the Earth, Vandalblas, and
Hull Breach myself.
Anyway, hope this was helpful and good luck with the deck!