Services that Home Inspectors can provide

I would like to compile a comprehensive list of services Home Inspectors can do with the license and peripheral certifications.
I learn about things I was not aware of on a regular basis. I was just on this forum, and saw something about acting as a 3rd party inspector for shingle companies. So sound off if you have knowledge of other Home inspector related offerings. When I say knowledge, I mean anything related to the service such as, contacts pitfalls, liabilities, peripheral certifications/licensing, target clients, income possibilities etc etc… (If you haven’t had first hand experience doing the service, and just know about it, list it, but refrain from selling the idea of it, or saying it is not worth doing.)
I look forward to hearing all the possibilities out there. I know you master home Inspectors probably just pass on a lot of opportunities, but I know you know about them. Remember; one man’s trash is another man’s treasure.