This auth lib has a nice set of features, including support for a bunch of oauth providers. What I really appreciate about a solution like this (vs relying on a 3rd party) is the own your own data bit:

• An open source solution that allows you to keep control of your data
• Supports Bring Your Own Database (BYOD) and can be used with any database
• Built-in support for for MySQL, MariaDB, Postgres, MongoDB and SQLite
• Works great with databases from popular hosting providers
• Can also be used without a database (e.g. OAuth + JWT)