I make my own flour mix - straight rice flour didn't have good results for me. Rice flour, brown and/or white, coconut flour with a little tapioca flour for cakes, and GF oatmeal flour for cookies and muffins. Xanthan gum is added at time of baking. I make my mix in a large quantity so I don't have to haul everything out each time. I like Namaste spice cake mix, Bob's Red Mill vanilla cake, and Tinayada brown rice pasta. My mix makes great choc chip cookies using any 'regular' recipe.
I can't have yeast or corn, either, so I so am really label reader. I'm sure you are aware no gluten means no barley or rye, either. Oatmeal is iffy. I can use Meijer's organic - my son in law can have none. Soy sauce is made from fermented wheat and the list goes on. Lauriejo is right. The closer to natural, the better.