This isn't an addon, but I made a bookmark with the URL https://web.archive.org/web/submit?url=%s and the keyword "rez". (You can add keywords in the full Bookmarks window, Ctrl-Shift-B.) Now I can load any page in the Internet Archive by putting the word "rez" in front of it in the address bar!
Temporary Containers: https://addons.mozilla.org/en-US/firefox/addon/temporary-con...
I use Temporary Containers in full Auto Mode, with all new tabs and links opening in new container.
Behind the Overlay Revival: https://addons.mozilla.org/en-US/firefox/addon/behind-the-ov...
Used for quick one-time removal of overlays.
uBlock Origin: https://addons.mozilla.org/en-US/firefox/addon/ublock-origin...
On top of basic ad blocking, I use uBO to more permanently block certain overlays.
In-Page Pop-up Reporter: https://addons.mozilla.org/en-US/firefox/addon/in-page-pop-u...
Part of a Mozilla experiment.
Referer Control: https://addons.mozilla.org/en-US/firefox/addon/referercontro...
Default Referer set as Custom: [TARGET_HOST]