My favorite add-on
But depends on the abandoned KeePassHttp project (last update on github 8 years) (-2 stars)
Would it be possible to switch to another KeePass plugin, e.g. KeePassRest?

KeePassHelper asks permanent for "new Key Association", association wouldn´t work. Anymore.

I've tested for several times,that "Generate a Random Password" function don't generate a length of 12 ,but actually 11. When i change the length to 13,it works fine.

Reregistrion fails. One has to remove and reintall the plugin to work with Keepass

https://github.com/Coool/Browsers-Add-ons-keepass-macpass-helper

Best credentials (username, password, PIN) Add-on (Extension) for KeePass for my needs. Supports not only local machine, but any machine in your LAN. Recent changes supports KeePass built-in OTP - https://github.com/belaviyo/keepass-macpass-helper/issues/62.

I have experience with Add-ons (Extensions):

Active:
KeePassXC-Browser (based on chromeIPass and some changes merged also from KeePassHttp-Connector) - https://github.com/keepassxreboot/keepassxc-browser
ChromeKeePass - https://github.com/RoelVB/ChromeKeePass
KeeWeb Connect - https://github.com/keeweb/keeweb-connect
Keywi - https://github.com/LEDfan/keywi

Inactive:
KeePassHttp-Connector (forked from chromeIPass/passIFox) - https://github.com/smorks/keepasshttp-connector
PassIFox (for Mozilla Firefox), chromeIPass (for Google Chrome) - https://github.com/pfn/passifox

P.S.
Check out my collection of Privacy & Security add-ons - https://addons.mozilla.org/firefox/collections/17493519/Coool-Privacy-Security

Using this flawlessly with the KeePass application with KeePassHttp on my local pc. Thanks!

Excelent plugin. Love it. Worked with one click.

Если и работает, то догадайся сам..........

Esperienza positiva da anni, molto comodo e efficente.

The pop-up mentioned in step 5 doesn't show whatsoever, so I'm not able to make it work.

Does not work. Have the necessary plugins in keepass desktop app as well

The autofill is a bit clunky. you can only autofill a single username and you have to write that username out explicitly completely. So I just copy it from the manager.

But I do use it and it does work. Until today it never even occurred to me to look for other extensions but if you're wondering about it. It works fine.