[InvaderFizz]

Not sure if this answers your question, but you can use a Yubikey for FIDO2 on iOS with any iOS device with a USB port, or use the camera connection kit to make one on a Lightning port device.

Source: I was curious, so I used a camera connection kit to login to Okta with a Yubikey as my MFA last month.

[turdnagel]

I was curious about the use case of using a YubiKey to unlock 1Password.

[weichweich]

You can also use it with NFC.