I also have found tools(and usually kept them, but happy to pass along any that are super-superfluous) such that I have a "notorious" reputation amongst my friends for finding such things.

But the best, which I just put to use a few days ago, was a Fluke multi-tester in its vinyl case, still works fine after a couple battery changes. Must have fallen out of a truck cause there was absolutely NObody on the road in any direction, certainly no active electrical workers on a job.

I lost count of all the other handtools that came into my hands over the years, but the needlenose visegrips are always disappointing me: they seem like a perfect tool for certain jobs but they almost never are!
Regular visegrips are just the opposite, they work as expected...go figger!

We should also have a thread concerning "bicycle parts found on the road"