For my gridfinity shelf I created a storage solution for microscopic slides. One container takes up 2x3 grids and holds 28 standard sized microscopic slides. For easy identification I also created 2d printed numbers you can put below the slides and a corresponding sheet you can write down the contents and glue on the inside of the lid. These can be regularly 2d printed on an A4 sized sheet of preferably adhesive paper (pdf attached). Also there is space for labels in the lid and in the base. These are designed to fit a standard 12mm DYMO tape. Feel free to change according to your needs (f3d file attached) and if you do so be fair and make it available for everybody else.
Printed on bambulab a1 mini with pla filament. No supports. Flip the lid for printing.