wow, you're nice on your bike, the most I have done yet is maybe pick up some trash if it is particularly noticeable in the immediate neighborhood.
Various times, I have driven by people's houses at the curb on trash night on my bike or come across bagsters and found some nice wood including some nice thick plywood to use at home for projects (this stuff is really expensive by the way), even a roll of brand new carpet that I use to cover a cat stand I made once.
Sometimes if I don't have the bike trailer with me and its large, I will hurry home hook up the bike trailer and return to get the find before someone else finds it first. I don't know if it this is "technically" helping someone else out but it is probably a plus for the environment because it is avoiding a landfill and going to a good use.