This workbench will allow you to generate assortment trays for Zack Freedman's gridfinity standard.

I started off by using the model by user 'Jamie': https://www.printables.com/model/174346-gridfinity-openscad-model, but ended up recoding everything.

You can layout your tray as you like by using the concept of html colspan and rowspan. You can add labels: all cells, or just the rows or columns or custom per cell. The size can be changed, you can add text to the labels and print them with text. You can also leave a cells blank so you can carve out your own feature.

The source code and detailed user guide is here: https://github.com/annevanleyden/trayfinity

Tested to work with version 2021.1 and 2023.05.05.ai15069. The latter works orders of magnitude faster, but can produce some artifacts (they printed fine nonetheless, ymmv). It also has some issue with the customizer and not all fields will show up. Safest bet is to use 2021.1.

I would have also liked my code to work in the Thingiverse customizer, but it gives me a syntax error. So you'll have to download the zip and open the 'trayfinity.scad' file in OpenSCAD.