There's always the Hindu view, which most of us know about.
But then there's the Pythagorean view, which held that being trapped in bodies was always a punishment for crime. As a consequence: “Troubles are good, but pleasures are always evil; for whoever has merited punishment must be punished.” Gloomy souls. . . .
And then there's the Druse view, which is that merit has nothing to do with rebirth. A saint may be born a beggar, a sinner a king. And then when the world ends, everyone is judged on their average. No one will be able to claim it was his situation that made him evil; everyone will have had a chance at every situation.
Lots of possibilities. Even in a fantasy world where the afterlife is not known, a religion that teaches it could have very odd views on the purpose of reincarnation.