I don’t recall anyone posting free designs or offering to sell, but @brooklyntonia made a great one where cranking a gear flips the switch.
And here is what happens when steampunk meets art deco, no longer for sale, but still provides some ideas.
Inkscape has a built-in gear generator. If you don’t want an actual gear driven light switch cover that badly, the big box DIY stores sell wooden light switch covers you could score with some Inkscape generated gears. I agree with chris1 and wouldn’t try a plastic cover. Odds are it’ll turn all melty and not hold definition or you’ll generate a small cloud of HCL and melt the inside of your glowforge.