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
Civic Token - Access to identity verification via the blockchain
Cotter - One-click phone number login and checkout
BlockScore - The intelligent ID verification system