Google Titan - A 2FA device to protect yourself from hackers
TypingDNA Authenticator - 2FA codes in your browser, secured by the way you type
Cotter - One-click phone number login and checkout
LoginRadius Authentication - Secure and robust authentication, SSO with user management
Authorizer - Authorizer is an open-source authentication and authorization solution for your applications.
Rapid 2FA - A painless way to add two-factor authentication to your site