Vimium - The Hacker's Browser.

hunt-n-peck - Simple vimium/vimperator style navigation for Windows applications based on the UI Automation...

Shortcat - Keep your hands on the keyboard and boost your productivity! Shortcat is a keyboard tool for Mac OS X that lets you 'click' buttons and control your apps with a few keystrokes. Think of it as Spotlight for the user interface.

Tridactyl - Replace Firefox's default control mechanism with one modelled on the one true editor, Vim.

Surfingkeys - Rich shortcuts to click links/switch tabs/scroll pages or capture full page, use Chrome like vim for productivity.

Vimac - Like Vimium but for macOS.