If you're willing to check how it works, then official instance is here https://passwords-fountain.com/, but you can easily create your own, even free of charge (you need only static site hosting).
I hope you'll like it and I'm opened to your feedback.
It's basically PWA app written in Preact with the help of other micro-sized libs like goober.js (CSS in JS).
Whole codebase can be found here https://github.com/kolodziejczakM/passwords-fountain.
If you're willing to check how it works, then official instance is here https://passwords-fountain.com/, but you can easily create your own, even free of charge (you need only static site hosting).
I hope you'll like it and I'm opened to your feedback.