CKEditor : CKEditor is an open source WYSIWYG text editor designed to bring common word processor features directly to web pages, simplifying their content creat...
NicEdit : WYSIWYG Content Editor, Inline Rich Text Application
Slate : Slate is a completely customizable framework for building rich text editors.
Slate lets you build rich, intuitive editors like those in Medium, Dropbo...
mmm.page : Dead simple, drag & drop personal websites.
Strut : An HTML5 Presentation Editor. A GUI / Authoring Tool for ImpressJS and Bespoke.js
Source at https://github.com/tantaman/Strut
an open source rich text editor based on HTML5 technology and the progressive-enhancement approach.
