LibreWolf is a custom version of Firefox, focused on privacy, security and freedom. It is kept up-to-date with the latest stable Firefox branch. It is available for most major GNU/Linux distros and also for Windows and MacOS.

I recommend disabling “resistFingerprinting” for a more seamless browsing experience. For the maximum privacy protection it should not be disabled, but I think most users switching from other browsers will find its side effects annoying. I also don't use any CanvasBlocker add-on (which is recommended when disabling resistFingerprinting) since I want to keep my browser as light as possible. It is recommended to use medium mode in uBlock Origin.

You can disable “resistFingerprinting” in LibreWolf's settings or directly in the config file. This is the content of my librewolf.overrides.cfg

defaultPref("privacy.resistFingerprinting", false);
defaultPref("privacy.clearOnShutdown.history", false);
defaultPref("privacy.clearOnShutdown.downloads", true);
pref("javascript.use_us_english_locale", false);
pref("intl.accept_languages", "cs, en, de, en-US");

You may want to use other language codes for accept_languages, of course. See LibreWolf config file for details about the cfg.

Sidenote: I do not recommend using Waterfox browser because its source code uses a very distinct (outdated) branch from Firefox, therefore it has security holes and also contains Google tracking code. Besides that it is a little bit more heavy on RAM and CPU compared to vanilla Firefox and LibreWolf (it's clearly missing some optimizations).

Mull is a great mobile browser, a privacy oriented and deblobbed web browser based on Mozilla technology. Available directly on F-Droid or after adding DivestOS official F-Droid repository.

If you are looking for more alternatives, check out the DivestOS page which contains a very good browser comparison table.