I tried all cookie manager addons and picked this one.

Simple and easy to use UI.

Use expressions like *ali*.* to get rid of all ali[express] cookies for example, as I did to fix a stupid website language bug

Fantastic. Does what it says on the tin in a no-nonsense, usable way. Just what I needed.

The interface is a bit "shocking" the first time one sees it, like some raw data spat out of a debugger, but it is, actually, very thorough and unobtrusive, showing all the information of a cookie or the cookies of a domain. It recognises user containers (cookie jars) and, the best part for me, it is fully compatible with Waterfox (the lifesaver after the series of Mozilla's Firefox's add-ons hell, which started with the obligatory certification, then the dropping of XUL, instead of just incorporating WebExtensions, and the last one, the absolute dumbness of letting all add-ons' certificates expire on 2019/May/04).

Only addon that helps me with Cookies Import/Export.