YubiKey - The YubiKey is a one-time password device for secure login with two-factor authentication
LoginTC - Simply Strong Two-Factor Authentication LoginTC is best in class. Effortless Administration. Intuitive User Experience. Cost-effective solution for all organizations.
Nitrokey - Email Encryption. Encrypt your emails with GnuPG, OpenPGP, S/MIME or your favourite email client.
DIGIPASS - DIGIPASS offers two-factor authentication solutions for mobile applications.
SoloKeys - Secure login made open and easy 🔒
Authy - Best rated Two-Factor Authentication smartphone app for consumers, simplest 2fa Rest API for developers and a strong authentication platform for the enterprise.