I really like the design of the version created by lx (https://makerworld.com/en/models/2063613-extension-holders-tool-grid-no-gaps#profileId-2228292) and have a bunch of them and ran into space issues.  To conserve space, I wanted to stack extensions in my ratchet drawer.  I didn't find anything already out there so I designed these to match visually with the lx versions I was already using.  There are short and tall sets in each drive size.  I wanted to keep things low to the plate so I tried to keep the maximum heights as low as possible so each drive size does have different heights.  The short set will fit under the tall set in their respective drive sizes.  On the head holder side, the mounting hole is spaced so that the short can be up tight to the tall with no gaps (with both openings in the same direction).  I did not align the shaft support side for them to be tight as they can fit in wherever they need to.  All of the screw holes are slotted to allow some tuning for fit if desired.

I am using Tool Grid's actual screws and I printed the plates designed by Seraph (https://makerworld.com/en/models/1179101-tool-grid-base-plate?from=search#profileId-1293395).

I printed on a P1S with Bambu PETG HF and Voxel PETG without issue.

These are 6 wall loops, 6 base layers, 6 top layers, and 25% gyroid infill.  Could be overkill, maybe not.  Time and filament savings can be had by adjusting those numbers to your preferences.