Maybe I can piggyback onto this thread actually.
I don't use 2FA because I see it as complicated and dangerous in that it's likely prone to me getting locked out, this is probably because I don't know what "good simple relatively universal device" exists.
I want something that...
1. Works at least with Google
2. Is not an app on a phone or a desktop, I do not carry or have a phone near me most times
3. Is small that I can hang on my keychain preferably, or similar form to a credit card (like the old SecureID card I used 20 some years ago)
4. Something that I can have at LEAST one, preferably two spares of, physically, just like spare keys, completely identical so that "it just works"
5. Works (in authenticating) on all platforms and devices, so likely means, does not need to be plugged into USB to use it for authentication (but setup could)
2FA afficionados - does such a thing exist?
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Edit to add: Seems like Limor Fried has similar desires -
https://hackaday.com/2018/01/04/two-factor-authentication-with-the-esp8266/ - so I want something almost the same like that, but not DIY (I could DIY, but I'm not motivated enough to DIY).