andOTP - andOTP is a two-factor authentication App for Android 4.4+
Google Titan - A 2FA device to protect yourself from hackers
Aegis Authenticator - Aegis Authenticator is a free, secure and open source app to manage your 2-step verification tokens...
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.
Nitrokey - Email Encryption. Encrypt your emails with GnuPG, OpenPGP, S/MIME or your favourite email client.