Older Firefox Add-Ons:

Adblock Plus - https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/

Always on Top - https://addons.mozilla.org/en-US/firefox/addon/always-on-top/

Open in MS Edge -  https://addons.mozilla.org/en-US/firefox/addon/open-in-microsoft-edge-browser/

Open With -  https://addons.mozilla.org/en-US/firefox/addon/open-with/

Ultrawidify - https://addons.mozilla.org/en-US/firefox/addon/ultrawidify/