If you are extra cautious about securing your online accounts with the best possible authentication method you probably know about Yubico. They make hardware authentication security keys to replace two-factor authentication and get rid of the password authentication system for your online accounts.
Basically you just plug the security key on your computer or use the NFC on your smartphone to unlock access to accounts. In this way your authentication method stays completely offline.
Of course you can always use a good password manager for Linux available out there. But if you own or work for a business or just extra cautious about your privacy and security and want to add an extra layer of security these hardware security keys could be worth a try. These devices have gained some popularity lately.
Yubicos latest product YubiKey 5C NFC is probably something impressive because it can be used both as USB type C key and NFC just touch your device with the key.