Python Social Auth¹ by Matías Aguirre is a great library that was abstracted from battle-tested Django Social Auth. Authomatic² by Peter Hudec is good as well.

Flask Social³ by Matt Wright is worth a look, too.

You can find example implementations with different DBs in the examples directories of the projects. I've used everything from Redis and MongoDB to SQLite to store user information. It all depends on your goals. My framework of choice is Flask most of the time.

[1] https://github.com/omab/python-social-auth

[2] https://github.com/peterhudec/authomatic

[3] https://github.com/mattupstate/flask-social