I wanted linkable trays to hold all my various sockets neatly and easily identifiable.
The attached OpenSCAD file allows the size of the tray, cutouts for tools and text labels all to be customised.
Simply measure tools, and enter the exact outside diameter in mm, in rows and columns as you would like them arranged. The tool automatically adds (an adjustable clearance) and centres the rows and columns.
There is a switch for each side to add lip so that trays can be clipped together.
Every adjustable parameter is at the top of the file so can be tweaked for your exact needs.
If you have problems with large flat items curling I would add some extra perimeters.