Authy - Best rated Two-Factor Authentication smartphone app for consumers, simplest 2fa Rest API for developers and a strong authentication platform for the enterprise.
Microsoft Authenticator - One app to quickly and securely verify your identity online, for all of your accounts.
Aegis Authenticator - Aegis Authenticator is a free, secure and open source app to manage your 2-step verification tokens...
Google Authenticator - Google Authenticator is a multifactor app for mobile devices.
FreeOTP - Open source implementation of the two-factor authentication HOTP and TOTP schemes.
andOTP - andOTP is a two-factor authentication App for Android 4.4+