As a niche product, track pad for feet could be nice. You can move the cursor using your feet, while leaving your hands using the keyboard. You slide around with one of your selected foot to move the cursor and use the other foot for right click. The clicks can be registered by lifting your feet with your ankle still staying on the pad and come back down to register a click. Hands-free cursor and potential improvements to health as we can move our legs more when sitting at our desk.