Luckily, 1Password has a 'correct horse battery staple'-generator these days as well.
For other questions I use answers that 'belong' to a friend or relative. My secret key is the formula for figuring out who that is.
Even knowing that you're using a formula is a bit of information. The type of formula is potentially thousands of bits of information. An attacker doesn't know whether it's a cipher, or a code, or something more complex, and only then can they begin figuring out the parameters to that formula.
Friend used to have a car with a keycode door lock. He just used 5555 or whatever. I suggested he use the address where the car was parked, or some hash of that. Wouldn't have to remember it! And it would vary some at least.
Someone then trying to fraudulently use my identity info, or for any kind of socially engineered attack, would lose out.
E.g. calling some financial service provider and trying to get a password reset based on D.O.B, mother's maiden name, or whatever.