I made this so I could clip it on my belt when I was on a ladder and needed a place to hold a few screws and a few 1/4" bits. I made it modular using heated thread inserts so I could easily swap out for different tools for different scenarios.
I used 
M3x5.7 threaded inserts 
M3x8 cap head bolts
10x3 N42 magnets
40x13.5x5 magnets
I printed in ABS
Layer Height = .16
walls = 4
infill = 20
supports = tree/auto/3 top interface layers/.1 top interface spacing
I am including steps files, the bit holder, magnet plate, belt clip, and bare accessory plate for customization, and a small single piee one my wife requested.
I am NOT a designer, I built this for myself and one specific need. I had a friend tell me I should post it for others. 
I called it multibits because my youtube feed has been inundated with multiboard lately, and it sounded funny to me.
I only inserted the threads I needed at the moment, but there are provisions and you can insert them for the entire grid. Just seemed like a waste to do more than I would use. I can always add them later as needed.