Here are some protein bars that I have found in different stores.
Luna Protein Bars ( Available at Target, Harmon’s, and I think Costco)
G2G -Good2Go ( I Found these at Good Earth)
NoGii (CVS Pharms, Shopko, many more using the online store locator)
High Protein, paleo, and kids bars
GNC has a list of gluten free protein bars as well.
Muscle milk powder and individual premixed milks are gluten free too.