Custom drivers

Register a SocialiteProviders driver which is not in the list, with the prefix of its columns:
app/Providers/AppServiceProvider.php
The user model then needs the gl_id field.

Sign in with another CrudAdmin

The crudadmin driver signs in with an administrator account of another CrudAdmin, which has OAuth enabled.
app/Providers/AppServiceProvider.php
config/services.php
The signed in administrator is read from user_path on the host. The default /admin/api/v1/user is served by crudadmin/api, install it on the CrudAdmin which signs in. ca_id stores the provider table and the id, e.g. admins_5. Use a string field.

Hooks

Hooks are global callbacks. Register them in a service provider.
app/Providers/AppServiceProvider.php
Throw SocialMessageException in any hook to stop the login and show its message. Other exceptions show the messages.error text of the config and are logged.

Events

app/Providers/EventServiceProvider.php

Success response

Stateless and JSON responses contain auth_token, expires_in and previous_path. Add your own data with SUCCESS_DATA_RESPONSE:
Return a response instead of an array to replace the whole response.

Using SocialAuth in your controller

app/Http/Controllers/Auth/SocialController.php
Turn off avatars of all drivers with SocialAuth::$photoColumn = null, or store them in another field with SocialAuth::$photoColumn = 'avatar'.