Just behind me where I am sitting at the moment I have 21 RUBs containing my collection of about 42000 pinned out flies (mostly). The RUBs are stacked in and on top of bookshelves. I seem to remember that you could buy a rack to hold them but it looked too flimsy for what I wanted. The flies are pinned out onto plastic foam sheets in small clear plastic presentation boxes, 48 of which fit in each 12 litre RUB. I still have to properly identify about half of the flies. Photos of the presentation boxes and CSV files of the identifications are backed up to https://github.com/tristrambrelstaff/flies. RUBs have played a significant part in enabling me to manage all this.

Thanks for the Really Useful Boxes referral. I've been using made in the UK Wham Plastics organizers and IKEA boxes, but front-loading is what I really need.

Second that. Our garage is full of their 50L boxes with the XL lid, perfectly fitting those industrial shelves. Very versatile and long lasting. Even after nearly ten years, they look pretty much the same, and we live in harsh climate near the coast.

Although looking at his, several of them are so covered in dots as to be opaque anyway.

I'd have maybe used different colored dots, e.g. N blue, then remove them and place 1 green etc. as a counter and so on.