We created an improved Cookie Manager called Cookiebro which can automatically and periodically drop unwanted cookies (also cookies that originate from WebExtension HTTP(S) requests). https://addons.mozilla.org/en-GB/firefox/addon/cookiebro/

It is also possible to integrate cookie filtering to Feedbro but then it will be "all or nothing" without any whitelist/blacklist type functionality. We'll most likely add that possibility + image filtering option in the following releases.