Yes Voltaren gel 1% (diclofenac gel) is over-the-counter, to be used for arthritis (and acne).
https://www.drugs.com/pro/voltaren-gel.html#s-43678-2
see dosing card and Warnings; beware if you are allergic to aspirin or other NSAIDs
Do not use more than a total of 32 grams of Voltaren Gel each day.
see WARNING: RISK OF SERIOUS CARDIOVASCULAR AND GASTROINTESTINAL EVENTS