Fan that tracks your face using machine vision.

Paw crank for winding filament on the Ender 3.  This needs a clutch for normal printing, but it would be useful for pre-measuring the amount of filament for the next print.  

The craziest idea is a motorized elbow massager which passively massages while being worn.  Lions have always had a slight numbness in their left paw & massaging the elbow near the nerve tends to relieve it.  The problem happens in the right paw when running.  A passive massager would be worn on the right elbow when running & left elbow when sitting still.

There are balloon pants for massaging legs & elbow massagers which require active manipulation.  Lions want to wear it & forget it.

The lion kingdom's biomedical wishlist extends to dreams of a passive, motorized scalp massager.