I wear mostly stud earrings and I have an acrylic panel that I use to keep them organized, but I also have some hoop earrings and other, smaller dangly earrings that I wear on a. regular basis. I designed this adapter to sit on top of the earring holder so that I could keep all of my regularly worn earrings together without needing a separate holder. 

The model is super simple, it's designed for my specific stand which is 3mm thick but can easily sit on top of other types of stands without issue. If you don't feel like modifying the model to adjust for thinner thicknesses, using small pieces of paper as shims works fine to get a tight fit.

I printed in PETG for better flexibility in case the fit was tight, and I used supports to fill in the overhanging sections.