I saw a Gentlemean, in Decatur, yer befer last, that had a large case with trays or boxes that contained all the small screws, bolts, fittings, fuses, bulbs, testers, and small tools that might be needed to work on the Motorhome.
I've lost his name. Anyway that would be ideal for the accumulating things, we need for the coach.
It fit one side of a bay and held, perhaps, 40-50 large drawers, and was nigh as high as the bay and near 2 ft deep. It was constructed of durable plastic.
In times past you could buy electrical connectors or bolts and nuts in a case of similar , if not small built.
Home Depot/Lowes carries smaller tray units that are about 18x18x6. They have a couple different sized trays for bulbs, bolts, and whatever else you would like to carry. The only downside is that the one I have doesn't have securing trays, so they could very easily spill contents all over the friggin place; works good for the garage though. I'm sure you could come up with something to keep them shut.
When it comes to tools and supplies I have found that the “OFF-SET” rule is always the strongest.
“The greater the need is off-set by the odds that you are carrying anything that even looks remotely close to fitting”
well I found a multi compartment storage box at Harbor freight two weeks ago, they were on sale. Gave one to my son, he does installations and he can use it. but I use mine for my RC airplanes. all the little parts you accumulate over time fit in very well.
clear plastic tackle boxes work good for me. Challenge is to keep inventory to a min. I also use a plastic storage box for dry stuff, elect cords, knee pads, emergency light, compressor, battery charger etc. And another one for wet stuff atf fluid, oil, cleaning fluids, spray lube etc