And as the option that you're wanting, there's one crypto that's very close to what you're thinking. There's none other than but bitcoin. BTC
And i believe for that reason there is a possibility that if the time pass by and if you lost your current back up there's no way you can remember the password you changed in it.. Then only thing you can remember is the common password that you used in your other accounts.. It happens to me actually and that really hard to remember.. So if i were you guys print it or carved it in a piece of wood metal and etc because that's the only thing that can really keep our private information even for long time..
I don't advise to have common passwords because if a hacker gets in then all of those accounts of yours can also be affected if the hacker tries to sneak into your other emails or accounts having the passwords and accounts.