django-allauth
Integrated set of Django applications addressing authentication, registration, account management as well as 3rd party account authentication.
Project Source: https://github.com/pennersr/django-allauth
Project Homepage: http://www.intenct.nl/projects/django-allauth/

django-social-auth
Django Social Auth is an easy way to setup social authentication/authorization mechanism for Django projects.
Project Source: https://github.com/omab/django-social-auth
Project Documentation: http://django-social-auth.readthedocs.org/en/latest/

rauth
A simple Python OAuth 1.0/a, OAuth 2.0, and Ofly consumer library built on top of Requests.
Project Source: https://github.com/litl/rauth
Project Homepage: https://rauth.readthedocs.org/en/latest/

python-oauth2
A fully tested, abstract interface to creating OAuth clients and servers.
Project Source: https://github.com/simplegeo/python-oauth2

python-social-auth
Python Social Auth is an easy-to-setup social authentication/registration mechanism with support for several frameworks and auth providers.
Project Source: https://github.com/omab/python-social-auth
Project Homepage: http://psa.matiasaguirre.net/