Take a look at https://lesspass.com
It's free, open source and multi-plateform/multi-browser. There is no synchronization and no storage. This is an interesting new way to made password. Just provide an hard password and lesspass does the rest...
I use supergenpass which works in a similar way. I would not use this for production passwords though as they often need changing which lesspass or supergenpass do not support
I also once used a similar service. Then one of my accounts was hacked and I could not simply change the password. It was very bad. That's why I left this idea and went back to a classic password manager.
btw, one should change their password for any account every few months to years no matter what ;)
In lesspass.com you can increase the counter, if first password is compromised, and get new unique password for same service. Also lesspass.com provide "connected" version to save custom passwords in database.