I store my electrical SMD components and other small parts in 2ml micro test tubes (eppendorf tubes) as they are cheap (got 1000 + shipping for less than 20 EUR), small and also easy to handle. I created this rack set to have them neatly stored. The base plate can hold 40 of the 2ml test tubes. The slots are designed to align the lids all in the same direction which makes it easier to read the labels on the lids. Also the test tubes can kind of "snap" into the slots, which prevents (or at least minimizes) "spillage" of the tubes if a rack is tilted. The mounted racks are stackable, the side parts have slots that prevent slipping off of each other. I included 2 sets of side parts (110mm + 170mm) that matches either the short or the long side of the base plate. Your choice!

For 1 rack set you need 1 base plate and 2 side parts of the chosen length. For the base plate i suggest >=50% infill to make it quite solid, especially if the used filament is a bit brittle. For the side parts <20% is sufficient (i used 15%) unless you want to give them to your dog as a chew toy. You might glue the parts together with some super glue.