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.
OTP Auth - The app for calculating one-time-passwords on iPhone and iPad.
Google Authenticator - Google Authenticator is a multifactor app for mobile devices.
Authenticator - Authenticator is a simple, free, and open source two-factor authentication app.
TOTP Authenticator - TOTP Authenticator app makes it easier to setup and manage your 2-factor authentication accounts and tokens. The app allows you to add extra security to your accounts and protects them from hijacking. Available for iOS and Android.