Quill - Your powerful, rich text editorquilljs.com/
Quill is a free, open source WYSIWYG editor built for the modern web. With its modular architecture and expressive API, it is completely customizable to fit any need.
Spacemacs: Emacs advanced Kit focused on Evilspacemacs.org/
Emacs advanced Kit focused on Evil
StackEdit – In-browser markdown editorstackedit.io/
Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.
VIM Adventures is an online game based on VIM's keyboard shortcuts. It's the "Zelda meets text editing" game. So come have some fun and learn some VIM!
ShareLaTeX, the Online LaTeX Editorsharelatex.com/
An online LaTeX editor that's easy to use. No installation, real-time collaboration, version control, hundreds of LaTeX templates, and more.