Dresden eyewear is one of my favourite solutions. The gist is that they come in a choice of colours in one standard shape, are relatively affordable to everyone, and look cool.
As I currently have three colours, one to wear and two alternatives, I need two protective cases that will keep them safe from getting crushed in a travel bag.
Here is version 1. The design is measured to fit Medium size frames, features an asymmetric honeycomb cutout, and is printed in transparent PLA.
You can download the zip file. It has the design Blender file and STL files (solid and honeycomb versions).