The ability to completely customize your browser with thousands of add-ons is one of the best features of Firefox.It completely change your experience on the web. They generally make life easier for you and increase your productivity.Firefox has some cool add-ons which make the job of website designers much easier. There are many useful add-ons for Firefox out there and we use several pretty much every day for work.
Now you can download Firefox addon collections categorized according to your needs and get the best extensions all in one go.
Check out here :Firefox-Collections