I recently picked up a set of PolarPro's Cinema ND and ND+Polarizer filters for DJI Mavic drone. They come in a nice box supported in foam but are a bit fiddly to get in and out.
Did some looking online and found a nice tool to allow you to keep your fingers off the filter glass.
The same person had also done a case that firmly holds the filters - but only for 4 filters.
So - I ran off a copy of the tool, but - I needed a case for 6 filters. And I also wanted them labelled with the filter strengths. So - the design was nearly right - just needed a bit of tweaking.
First off I modelled it in Fusion 360. The idea is very much the same concept as the one on thingiverse just with 6 slots and labels that match the set of filters.
The inner rings are just the right size that the filter grips them as it does the mavic camera, the slots around are just large enough for the tool to easily grab and remove or insert the filter. The rings in the lid are just long enough to hold them in place to prevent rattling when the lid is on.
And then I sent them to the printer.