Vimium-FF – provides keyboard shortcuts for navigation and control in the spirit of Vim. - eviltoast
Vimium-FF – Get this Extension for 🦊 Firefox (en-US)
addons.mozilla.org
Download Vimium-FF for Firefox. The Hacker's Browser. Vimium provides keyboard shortcuts for navigation and control in the spirit of Vim.This is a port of the popular Chrome extension to Firefox.Most stuff works, but the port to Firefox remains a work in progress.

Very useful and pleasant to use. You almost don’t have to move your fingers out of the keyboard with this extension.