Amazon Cognito - Amazon Cognito lets you add user sign-up, sign-in, and access control to your web and mobile apps quickly and easily. It scales to millions of users and supports sign-in with social identity providers and enterprise identity providers via SAML 2.0.
NoPass.me - Open-source identity verification
Authentiq - Strong authentication, without the passwords
Authenteq - User-owned and controlled blockchain-based online ID
Cotter - One-click phone number login and checkout
Velix.ID - Frictionless Identity verification through Blockchain