A simple parametric potentiometer dial in OpenSCAD. There's really not a whole lot to say about this.

You'll notice in my photos I'm having some platform stick issues to work out right now, and therefore couldn't quite complete a print of the dials without the whole thing coming unstuck partway through -- but fortunately this happened late enough in the print that the dials are still perfectly usable.

Print as many as you need using Multiply.

Should be sized perfectly to slip right on a ~6mm potentiometer shaft.