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
Rapid 2FA - A painless way to add two-factor authentication to your site
Auth0 - Auth0 is a program for people to get authentication and authorization services for their own business use.
Authorizer - Authorizer is an open-source authentication and authorization solution for your applications.