One of the most interesting features of YubiKey is the ability to use it to store the private key for SSH. With Elliptic curve algorithm, usually ED25519 you can just use the -sk suffix to ask ssh-keygen to create SSH keys that resides inside your physical YubiKey.
▬ Contents of this video ▬▬▬▬▬▬▬▬▬▬
00:00 - Introduction
01:18 - Create your first key
04:14 - Copy public key into remote server
06:45 - Access your server with SSH key from your yubikey
08:13 - Use config file to specify user and key for each server
09:25 - Conclusions