At krypt.co we’re building the next generation of mobile-based authentication. Our vision is that authentication should be based on strong cryptography.

List of websites and whether or not they support One Time Passwords (OTP) or Universal 2nd Factor (U2F).
Also see the list of dongles and the protocol they support.

@Puri_sm is happy to announce the addition of the Librem Key to the product line. Be able to fully secure your laptop and quickly determine if your laptop has been compromised at the bios level!
source : https://twitter.com/Puri_sm/status/1042977718868951040

Solo.
The first, open source, security key supporting FIDO2.
An upgrade to U2F Zero.