New "toolbar" that uses forgotten space Rated 5 out of 5 stars
With this add-on, I moved the bookmarks toolbar behind the entries of the menu bar. Then I changed the icons of my bookmark(let)s there to symbols with the add-on "Bookmark Favicon Changer". After erasing the title of the bookmark(let)s and adding some placeholders, I now have a new symbolic toolbar and am finally using the forgotten space in my menu bar!
At the moment, I have the following new "tools": remove redirects, increment and decrement last number in URL, open linked images in new window, make numbered list of images, open (selected) links, target new bg windows, router configuration, PrintWhatYouLike, about:config.
See screenshot below to know how it can look:
Icons (free) from: