[jopsen]

I use my yubikey for 2FA (TOTP), GPG/SSH.

I use an encrypted github for passwords storage: https://www.passwordstore.org/

For backup in case I loose my key I have multiple yubikeys, and whenever I setup 2FA on a site I take screenshot of the QR code and store it in an encrypted tarball in my password-store.

To duplicate my yubikey you'll need one of my yubikeys; and the password for the tarball (which is thus encrypted twice).

[xur17]

I use my yubikey with Password Store as well and absolutely love it. One of my favorite features is the ability to use my passwords in personal scripts / programs without having the save the password in the code. Instead I have the program call out to the password store binary to retrieve the password.