I finally pulled the trigger on this project. Here's the result---my hardware store/drawer
short and long screws on top layer (still waiting on the Prusa for some more containers)
Nuts and washers on the next layer
Set screws and misc screws with same thread on the bottom row
So far it's been great. I've run into several situations where ordering a screw would have put me back several days but I found what I was looking for in the hardware drawer. I still have a few holes in my tap/die collection, though.
There was a fair amount of extra stock, especially for the larger size screws. I've got those stored with my other bulk materials, just out of easy reach. They're jumbled together but separate boxes for inch and mm. Most of them are the larger sizes so I think it will be manageable.
I purchased everything from McMaster. I didn't re-order anything I already had and I had to make some judgement calls on the sizes of some of the items. Short lengths of 4 x D are pretty reasonable until you get to the larger diameters, when it starts to look a little too long. Long screws 8 x D get really too long in the larger sizes. And YMMV in other ways, like whether you want #0 or #1 screws or if #12 makes sense for you. On the metric side (the plantain instead of the banana) there's judgement calls you need to make about the smaller screw sizes. In the end, it was 1500 $ plus the cost of the PLA for the containers, probably another 200 $. So it's not cheap but it kills me to pay 10 $ for shipping for a single size of screw. You could probably make an argument for the project based on shipping price alone but for me, it's about saving time, keeping momentum, and injecting some certainty into difficult projects.
Finally, the socket head cap screws can be modified to be low-profile heads, a sort-of flat head, or a button head. Obviously, the gray haired machinists are clucking and muttering under their breath. It's not a good idea, for the most part, but if you're in a hurry... You can always order the correct thing and install it later. Same for stainless fasteners or steel with other finishes.
Another great resource was the school district where I used to live used to have ”garage sales” where they sold off stuff insanely cheap. I didn’t see any storage but got several great HD tables that I still use in my shop now. They also blew out a bunch of sound proofed cubicle divider walls for almost nothing. Also got a bucket full of the same castors like what your carts have for $15 at a neighbors yard sale. Medical stuff is good stuff!