What is a good offline website auto-login manager addon?

[avada]

Hi!

I want a good auto login addon, that logs me in automatically on various websites, without prompts, preferably in the background.
I want it to be offline, so that passwords are only stored locally in an encrypted form and not by some web service. I don't like the idea to be dependent on a remote server that may or may not be running, plus it's an extra risk.

Does anyone know of such? So far I only found web service based stuff which I don't care for.