These baseplates fit the Harbor Freight large sized small-parts organizer (this one). I included two variants, the minimal baseplate and the skeletonized version with magnets. The magnet holes are sized for press-fit without needing glue.

I also made some for the “medium” size: https://makerworld.com/en/models/32681. Although they look like they are the same size, for some reason the HF cases are a few mm different.

I usually try to provide both STL and STEP files for my models, but the STL are mostly for previewing here before you download, and you should use the STEP files if your slicer supports them.