A long time ago, I bought a book that promised to describe forty-five compelling characters that I could use in my fiction. As I read it, I realized that I knew someone who resembled each and every character it described. And there were forty-five of them! Wow!
But I realized something. The author simply described eight basic personality types that can be found in any psych textbook. But each type could be either positive or negative, which doubled the eight to sixteen. Then each of those sixteen types could become either major or minor characters, which doubled the already doubled number. And so on, until forty-five distinctly different fictional characters were fleshed out.
I thought, hey, if that author could come up with forty-five characters from a list of eight basic personality types, I could do the same with any similar list out there. And there are several different personality type lists out there. Just google the term and see what comes up. Then do what that author did, consider each type from different perspectives. And you, too, can come up with all the characters you could possibly ever need for all the books you ever intend to write.
Of course, there’s a caveat. I read the book, enjoyed every page, then ignored it. I suggest you do the same. Because, though people truly can be categorized, everyone is unique. So use the descriptions as basic guides, then flesh them out however you wish. The resulting characters might resemble people you know. Or people you can’t believe exist beyond your books.
Either way you’ll have wonderful characters to populate your wonderful stories.