What kind of Protein Powder should I take? (Pro Question)?

I'm interested in this as well, albeit probably for a different reason. I don't want any filler because I recently started having problems with my corn allergy again and the GNC one I have right now has xanathan gum, which is often derived from corn. The other one I have has erythritol as a sweetener; again, a corn product. ;( So if anyone answers this and has brands without fillers and esp. without anything made from corn, I definitely want to hear about it please.