Use your surplus bit holders as a mini screwdriver and store it together with a 26 bits in a Gridfinity storage box. 

This Mini Screwdriver uses standard bit holders as the core and wraps it in a nice feeling handle. It has two versions available; one round and the other with a flat side. 

Print instructions

The Mini Screwdriver should be oriented upright. It does not need supports, but it helps to add a brim as the surface area is quite small. A minimum of 4 walls is advised.

The Gridfinity box can be printed face side up or face side down, depending on your printer supports may be necessary for the Screwdriver space.

I've printed it with eSun PLA matte black, but PETG and ABS shouldn't be a problem.

Assembly

The housing is designed to hold the bit holder at the narrow section at the bottom of the bit holder. 
The bit holder should be pressed in with a bit of force and is then held securely.

A step file is included.