We use AEM as a CMS in a C/C++ based product.
we used the traditional username/password approach.
we need to integrate the oauth mechanism into our product.
We do not have any custom plugin/packages for AEM written.
The AEM OAuth server functionality support this directly(AEM as a OAuth server) - Refer https://youtu.be/kk945DABg8Y for more details.
Refer https://medium.com/@techforum/social-login-with-linkedin-adobe-experience-manager-aem-53c38ce22780 if you want to enable custom OAuth provider integrations(AEM as OAuth Client).