The easiest way to find more bars is to simply look at the nutrition labels at the store and scan them for any nut ingredients. It should say whether it contains nuts as a disclaimer, too. Keep in mind also that many food items and supplements are processed on shared equipment that is also used to process nuts, so there could be trace amounts of allergens introduced even if there are no actual nut ingredients. It should say this on the packaging as well.
Some brands that make peanut free protein bars in peanut-free facilities include: ZEGO, 88 Acres, No Nuts!, Libre Naturals, Raw Crunch, Avalanche, Rise, TANABAR, Paleonola, Kubeba, and Go Raw.
Another option is to make your own nut free protein bars! There's lots of tasty recipes you can find on Google and YouTube that incorporate protein powder. This might also be an inexpensive and healthy alternative to buying the protein bars at the grocery store.