Someone with a great deal of experience in a given field could use their expertise to produce a video or audio tape about their area of expertise. Write a book or develop a guide. Use your knowledge to write a book. It's a great way to become perceived as an expert in your field. Organize a seminar that could be used by trainers in various markets.
Seminars are a great way to reach a lot of people.
You might as well share what you know. Create a catalogue. Most service industries have trade journals. However, there may not be a catalogue of the supplies, information, or goods needed for those businesses. Someone involved in an industry is a likely candidate to create such a catalogue.