I have been looking for just a simple Dremel bit holder without all of the extra places for sanding drums and cutoff wheels and accessories. Not being able to find what I was looking for, I just decided to make my own. It has 105 slots, about 1/2" (12.5mm) apart. There is nothing fancy about it, but it's exactly what I was looking for. I can store my Noga deburring tool bits in there as well.

Note: I kept the tolerances fairly tight, so you may need to adjust your X-Y Hole Compensation. I set mine to 0.12 and it was perfect.

Centauri Carbon
0.28 Layer Height
2 Wall Loops, 7% Infill
PLA