I took Prusa's herringbone gear, converted it to be parametric using Fusion360's built-in mesh-converter, and added a hexagon around it, so you can use it like a fidged spinner

I made 15mm, 12mm, 10mm, and an 8mm version.

8mm is definitely tough to print, but with leveling dialed in, you can pry the elements loose and add some WD-40 to make it really smooth ;)

The ones in the 3rd & 4th picture are 10mm versions, scaled to 125%.

You can do the fuzzy-skin effect with the provided modifier file like so: