6x3 6u stackable gridfinity bins.  I use them for organizing my screwdrivers.  Not fully in line with the gridfinity mentality, but I like a good compromise and this fits the bill for me.  I can have my screwdrivers organized but without having to be super picky about which one goes where.

I like printing the top 10mm or so in a different color, and then using the color to easily tell what goes where: blue for flat head, red for phillips, gold for allen/hex, etc.