uBlock Origin, Disconnect, HTTPS Everywhere, Privacy Badger, NoScript, Self-Destructing Cookies, Decentraleyes, Privacy Settings, and Clean Links.
(N.B. the first four of these are also available in Chromium-based
I use Chrome as a secondary browser, with the first four of
the aforementioned extensions, plus also Clear Cache and occasionally Flashcontrol.
This one has nothing to do with security or privacy, but Reedy on Chromium is a really nice tool for speed reading.