Maybe some type of long physical probe you have to sit on and it generates a hash from the exact shape of your "cavity".

Seriously, am I the only one who was happier without any of this "2FA" crap? VPS/Domain/Google with a hardware token is the one narrow scope where I see any value, and even those I could do without. Every other site is just a non-consensual nagging that hassles me when logging in. Bank accounts are the worst, as every bit of friction for checking my balance/transactions actually decreases my security!