goauthentik
The authentication glue you need.
ory
Internet-scale OpenID Certified™ OpenID Connect and OAuth2.1 provider that integrates with your user management through headless APIs. Solve OIDC/OAuth2 user cases over night. Consume as a service on Ory Network or self-host. Trusted by OpenAI and many others for scale and security. Written in Go.
doorkeeper-gem
Doorkeeper is an OAuth 2 provider for Ruby on Rails / Grape.
DefGuard
Zero-Trust access management with true WireGuard® 2FA/MFA