uBlock Origin : https://github.com/gorhill/uBlock
Privacy Badger : https://www.eff.org/privacybadger
Tab Memory Usage (legacy mode as not supported on v57) : https://addons.mozilla.org/en-US/firefox/addon/tab-memory-us...
WhatRuns : https://www.whatruns.com/
Boomerang for Gmail : https://www.boomeranggmail.com/
about:addons-memory (legacy mode as not supported on v57) : https://addons.mozilla.org/en-US/firefox/addon/about-addons-...