Seamonkey (which I'm using to write this) is one option. Built for all platforms, no Mozilla tracking/ad/pocket-partnership nonsense. Unfortunately the team is

Seamonkey (which I'm using to write this) is one option. Built for all platforms, no Mozilla tracking/ad/pocket-partnership nonsense. Unfortunately the team is small and Gecko has been changing a lot lately. Long term the gemini protocol and browsers like lagrange might be the only option - its just too hard to build a modern standards supporting web browser these days (even Microsoft has thrown in the towel and adopted Chromium for Edge).