I find a blend of multiple types works best (a bit of hazelnut, coconut, rice etc with some xantham gum). Or buy a premixed packet- the select woolworths brand is the best value I think, although the Laucke's is probably a better flour.
I've used rice flour, almond flour and arrowroot (or tapioca flour) quite successfully when baking biscuits and pastries. Ground Chia Seeds and Flaxseed can be used instead of xantham gum.