andOTP - andOTP is a two-factor authentication App for Android 4.4+
YubiKey - The YubiKey is a one-time password device for secure login with two-factor authentication
Aegis Authenticator - Aegis Authenticator is a free, secure and open source app to manage your 2-step verification tokens...
2FA Authenticator - Simple 2FA Authenticator - Generate Two Factor Authentication tokens.
OTP Auth - The app for calculating one-time-passwords on iPhone and iPad.
U2F Zero - A secure and open source 2 factor authentication token. Designed to be affordable and reliable.