I'm one of those types that don't use any add ons. Just the bare bones browser. Just two actually, the Tor browser (which is based on Firefox) and plain Firefox. I even go into the settings and disable a bunch of different things, don't save any history, don't save anything, and rearrange the icons to somewhat resemble some classic look.
I use a handful of add-ons, but they are all directed at doing what you are doing: Increasing privacy and security whilst decreasing tracking. Even if you are aiming for the "bare-bones", I would still recommend uBlock Origin, HTTPS Everywhere and Privacy Badger.
I'd be interested to know which settings you are changing in Firefox or Tor? Do you just mean the ones under Tools -> Settings, or anything more advanced? I have quite a list of things I change in about:config whenever I am installing/reinstalling Firefox or Tor, everything from limiting the Referer header to refusing/auto-deleting cookies, and I'm always on the lookout for any more changes I could be making.
I also use DDG as my default search engine, and occasionally searX if DDG isn't finding what I want. Startpage used to be good too, but was recently bought out by a company which tracks you to serve you targeted ads, so is now just a privacy-invading as Google.