Rename Email - Easily change the subject of any email, by cloudHQ
NoPass.me - Open-source identity verification
WhoApp - Know who's calling before you answer
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.
Rapid 2FA - A painless way to add two-factor authentication to your site
Civic Token - Access to identity verification via the blockchain