andOTP - andOTP is a two-factor authentication App for Android 4.4+
Authy - Best rated Two-Factor Authentication smartphone app for consumers, simplest 2fa Rest API for developers and a strong authentication platform for the enterprise.
Aegis Authenticator - Aegis Authenticator is a free, secure and open source app to manage your 2-step verification tokens...
Protectimus - Protectimus multi-factor authentication solution is powerful and flexible, and scales to meet the needs of any business
OTP Auth - The app for calculating one-time-passwords on iPhone and iPad.
Duo Security - Duo Security provides cloud-based two-factor authentication. Duo’s technology can be deployed to protect users, data, and applications from breaches, credential theft, and account takeover.