I use Mullvad Browser. It's maintained in coordination with the Tor Project, and is essentially the Tor Browser with Tor itself stripped out. Same browser fingerprinting protections, however, among other things.
EDIT: I'd like to clarify that this has nothing to do with my trust in Mozilla or Firefox itself, especially not concerning recent panics about benign changes. I still use Firefox on the side, it just does not have fingerprinting protections by default, and hardening it manually leads to minor differences between user configurations (even with Arkenfox if that's still around) that is solved by Mullvad Browser for me. I use Mullvad Browser for my main browsing, and Firefox for specific exceptions. Firefox itself is fine, and no, Mozilla is not burning it to the ground.