VivaldiFox - An add-on that allows colouring Firefox in a Vivaldi style fashion
Dark Reader - Reduce eye strain in your browser with this extension that provides a dark theme for browsing.
automaticDark - Time-Based Theme Changer - Set Firefox to change the UI to a dark theme during the night and change back to a light theme during the day!
Dark Night Mode - It is a universal night mode for the entire Internet.
Dark Mode - A global dark theme for the web
Multi Copy Paste - Unlock 10 additional copy and paste