A modular drawer system based on my 10inch server rack:

https://www.printables.com/model/1182834-10inch-modular-rack

The drawers are 1u deep. The rack blocks are 1u tall. However, the drawers do not have to line up with the blocks, so you can add extra height between drawers if you want.

Print as many, or few drawers as you like.

Each drawer needs:

4x rackblocks (for the case)

1x each of inner&outer slides L&R (4 parts in total)

2x drawer fronts  - one of these is bolted to the rear rackblocks and the outer drawer slides for support at the back

1x drawer back

1x drawer bottom

30mm + 35mm m6 bolts

M4 screws

Self tapping screws (or heatset inserts into ends of drawer sides)

In addition, to make the top and bottom of the case, you need:

8x rack blocks

1x matrix plate for the bottom

then either:

1x “simple hollowed plate” OR “matrix plate” OR “gridfinity assembly” for the top (depending if you want m6 threaded holes, or a gridfinity rack on the top.

The “simple hollow” plate can be mounted hollow side in, or out, depending on your preference.

The cases are held together with m6 rod running vertically through the holes in each “rack block”

if you require a bit of clearance between drawers, add a m6 washer between each rack block in the vertical stack

If you want to expand the case sideways, print “double blocks” to replace the single blocks on whichever side you are expanding

I'll be adding to the design as time goes on: multiboard sideplates, gridfinity drawer bases, and taller/wider drawers are planned