Most of the bigger-ticket items require a doctors script. Same with things like allergy medicine, cough syrup, eye drops (except for contacts). My FSA does allow me to roll over up to $500, check with your HR department.
I buy nice sunscreen from either Walgreens or the FSA store. I compare the EWG list (https://www.ewg.org/sunscreen/) and what I can find online.
I've also bought heating pads, glucosamine such as Move Free (mine includes Vitamin D), ice packs, thermometers, bandaids, a TENS-unit, etc., over the counter.