For anyone concerned about hardening their browser:
While several people have posted extensions, and a few about:config tweaks, I've not seen the 'full set' covered. Mozilla have a Wiki covering some extra settings you can (should) tweak. Better yet - especially if you want to really harden things, but don't run Tor - is
LibreFox. It's essentially the ghacks config file (all privacy/hardening tweaks plus a few performance ones), plus some optional extra stuff. You just download the latest release from Github, extract, and copy/overwrite into your Firefox directory. Simple. If you're worried about breaking your profile or whatever, you can easily download the latest Firefox from Mozilla, extract it to a directory and apply Librefox to that and then run the two separately.
LibreFox doesn't allow cookies, sets all tracking protection to strict, blocks fingerprinting, disables various DOM settings like battery/mouse/screen, and enables isolation etc.
I'd also highly recommend Privacy Possum, uBlock Origin, Nano Defender, Decentraleyes, Local Sheriff, NoScript Security Suite and a cookie manager like Cookie Auto Delete. While I'm stuck on hardened Chromium on Linux (for hardware video acceleration), I use FF65 everywhere else with LibreFox and the extensions listed. Privacy Possum will further protect you from fingerprinting btw; something Badger doesn't do.