If you woke an insurance agent in the middle of the night and asked: "Who are Centers of Influence?" they would likely shout out: "Lawyers and accountants" then go back to sleep. True, but are there any others out there?
1. People who advise others.
That's why attorneys and CPAs top the list. Pastors and religious leaders would also fall into this category. Although the person approaching them isn't paying for their advice, they are often seen as someone who helps others.
In most of these cases, the person asked needs a "safe set of hands" when they send them to someone who might be able to help. You want to be that "safe set of hands" or at least one of the several options they will suggest.
2. People selecting speakers for groups.
Many local organizations feature speakers at regular meetings. Your alumni luncheon club is one example. Service clubs are another. What about homeowners associations that need to provide a full calendar of events? This is tougher than it sounds.
If they rely on their own contacts, they can run out pretty quickly. They also need to have a "Plan B" last minute cancellations or weather events leaves them without a speaker. They will be wary of people selling, so educational topics would probably get a better reception. Provide a list of topics you can address. You will need 15, 30 and maybe a 45 minute version of each, because you are conforming to their timetable.