Do you have OSH or Orchard Supply Hardware stores in your area? I am continually amazed at the variety of fasteners and hardware these guys carry. Small bearings, bushings, roll pins, inside and out C-clips, snap rings, woodruff keys, seals, o-rings, springs, gasket material and my eyes can't stop spinning. When I'm in any of the local auto parts store I give them hell for having such small selections of bolts, that are usually mixed up.
I am not connected with them in way. It's just that in my area, no one store has anything close to their selection.
Oh, you wanted bolts. Flange bolts and nuts?
Course or metric? I have to say that they did let me down about three weeks ago. I needed a flanged metric bolt for my AC braket 110mm long, they only had them up to 100mm.