I have been looking for a storage solution I can carry in my marbles in my pocket. I found a guy on Etsy that does 3d printing. And he will do custom orders. So I designed an insert, and sent him the drawing. He did a great job.
https://www.etsy.com/listing/4303036410/seven-star-altoids-tin-tray-insert?ref=shop_home_active_4&pro=1&logging_key=0f8334b73d5c85db3e65bee419a9012a71058fa3%3A4303036410
https://www.etsy.com/listing/4303033942/seven-star-round-tin-tray-divider-insert?ref=shop_home_active_5&pro=1&logging_key=303f4e7ba074833ac3e2854138320dab0531661c%3A4303033942
https://www.etsy.com/shop/FabricationFactoryCo
BTW, marbles are from the following makers: Matthew DeGraffenried, Timmy Walden, Paul Davis