Portier - An email-based, passwordless authentication service that you can host yourself.
humanID - humanID is a one-click anonymous SSO that provides users with an anonymous identity layer.
OpenID - OpenID is a safe, faster and easier way to log in to web sites.
yiid - yiid - Your Internet Identity - Simplify your community life
IndieAuth - IndieAuth is a way to use your own domain name to sign in to websites.
OAuth - OAuth is an open standard for authorization. It allows users to share their private resources (e.g.