Yes, vimium is available on FF. I’ve been using it for a while now.I use Chromium + Vimium extension to browse using keyboard which I believe is also available in FF, not sure about other browsers.
Vimium - The Hacker's Browser
vimium.github.io
That's why I use Opera.Well at the moment I am liking Icecat it comes with buitin Adblocker.