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!

Lost toolbar icon since v0.7.0.
Meaning that the LOCK icon is lost.
The icon is now default ADDON icon.
0.5.0 is OK.

Excelent plugin. Love it. Worked with one click.

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

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.