Just noticed this thread, otherwise would have responded sooner...
Are you in the Twin Cities? If so, check out Ax-Man Surplus stores. They have one of the larger selections of electronic components in B&M stores I've seen these days. Everything from LED's to reed switches, diodes, SPDTs, capacitors for a 1968 washing machine, and all sorts of other things that I have no idea what they are used for. Wiring selection is so-so (i.e. I haven't seen much fine gauge wire like for inside a locomotive). But just visiting the store is fun, they have all sorts of weird surplus things you never thought you might need, including various hobby-related supplies such as mini tools, cutting mats, or a set of glassware marked "PROM 2018 A NIGHT TO REMEMBER!" The best part is the all the signs they have on items around the store are hilarious. I was just there the other day and, for example, there was a box of small black electronic fittings with a flange on one end. The sign said, "Miniature Top Hats for small pets." Another was a bunch of rounded electric box mounting plates, labeled "Safety Ninja Stars." I think the St. Paul location has better selection than the one in St. Louis Park; I've not been to the one on the north side of town.
There's also Microcenter, in St. Louis Park. Primarily computers and electronics, they do have some supplies such as soldering equipment, breadboards, and a limited selection of components such as LEDs, transistors, etc.
Like others above, for some things like suitcase connectors, I've just ordered off Amazon.