IDK off the top of my head, but there are lots of history books and whatevers that you can read it from. I have a book on my shelf called Eyewitness to the Old West that is just a collection of journal and diary entries from settlers and people back when things were still wild. One of the stories is about coming across a tribe enslaving a person from another tribe, and the other tribe didn't keep slaves. But I don't know if they mention the tribe names.

I could guess, but they'd just be guesses.