Mainly Firefox. It has quite a good extensions engine, but the overall UX just still isn't there compared to other browsers. I really don't care about all the ethical or moral reasons people try to come up with for using it, I just want a browser that has a lot of good functionality in comparison with Edge or Vivaldi.
And while I am aware of some of the forks like Floorp and Librewolf, I find the latter to be too hardened, and the former to be behind compared to upstream.
This is the one I'm using, if anyone needs another suggestion. I also have some local modifications to remove the minimum tab size. I don't have a hoarding problem.