You can always use a hardware key like a Yubikey. The additional options discussed in this article are are to: 1. use a platform feature to have the TPM or Se

You can always use a hardware key like a Yubikey. The additional options discussed in this article are are to: 1. use a platform feature to have the TPM or Secure Enclave in the device itself work as an authenticator as an alternative to a hardware dongle. 2. synchronize across devices within an ecosystem (e.g. all Apple devices) using a mechanism on top of the platform account (aka AppleID + iCloud Keychain). 3. allow a phone to be used to authenticate to a desktop, even across ecosystems. The previous way would be to use a hardware key like a yubikey. If your platform supports #1, most sites _should_ support user management of a set of appropriate authentication mechanisms, and may even prompt on a windows desktop "would you like to use Windows Hello to sign in more quickly in the future?" A version of Windows has support for #2 might let you instead have that credential be added to every windows desktop or laptop on your account. Due to the variability of Linux, my suspicion is that each browser will fill some of the gaps there as well.