This modular hex bit organizer can be customized in many different ways. There is a total of 6 different section types you can print and snap together and you can add more later as needed. Add custom text, change colors, make it as long or short as you want. The sections are:

1 row x 6 bits evenly spaced
2 rows x 6 bits evenly spaced
1 row x 8 bits evenly spaced
2 rows x 8 bits evenly spaced
1 row x 7 bits progressive width spacing 
1 row x 8 bits progressive width spacing reversed

For the first top row print the "Topper" version, all next rows are the "Hex Bit Holder" versions.

These snap together very tight, use .16mm or .12mm. If you use .20mm they may not work correctly as they will be too tight to snap together. I used some custom settings to add strength to the .12 High Quality option but the extra strength isn't really necessary. I printed in PETG and didn't try any other filament types.

You can add labels in the slicer, I used Courier New 6mm and the height is 1mm to match the borders. I then painted the color down a depth of .5mm to highlight the border and text.

If you want to make your own custom sections the overall width is 132mm and height is 12mm. Each connector is spaced in 30mm from the edge and they are 10mm wide expanding out 2mm at 45 degree angles to 14mm. The male connectors are 8mm high and the female are 8.2mm high. The borders are 2mm wide and 1mm high.