OpenID - OpenID is a safe, faster and easier way to log in to web sites.
OneLogin - On-demand SSO, directory integration, user provisioning and more
Portier - An email-based, passwordless authentication service that you can host yourself.
TeamPassword - TeamPassword helps you manage and share access to the apps, services, and tools your team needs to keep projects moving.
IndieAuth - IndieAuth is a way to use your own domain name to sign in to websites.
Teramind - Teramind provides a user-centric security approach for monitoring.