I designed this to allow me to mix and match storage options while using the same box design. The removable holders can store hex bits, 3.2 (1/8") and 6.4mm (¼") and 8mm router/dremel bits, or small parts. Boxes can also be divided up into parts with dividers.
Each box can hold 5 dividers giving a current capacity of 20 bits in a 2x1 box.

Includes two box options, one with standards Gridfinity magnets, and one using a single 10x3mm magnet in the middle.

I'll expand on this idea in the future.

Update 16/01/23 - Added 4mm hex bits option. loosened tolerances on 1/8 and ¼ bit holders.
Added 3.5mm hex bits option for slightly smaller hex bits.

Update 22/01/23 - Added partition and end labels.

Update 03/02/23 - Added 8mm bit partition.