Edtr.io - Intuitive WYSIWYG web editor, open source & fully adaptable.
CKEditor - Real-time collaborative future-ready rich text editor
MathType - The Professional version of Equation Editor- MathType is a powerful interactive tool for Windows and Macintosh that lets you create mathematical notation for word processing, web pages, desktop publishing, presentations, and for TeX, LaTeX, and Math…
Summernote - Summernote is a JavaScript library that helps users create WYSIWYG editors online.
yEd - yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.
Froala Editor - Froala Editor is a WYSIWYG HTML editor that enables rich text editing capabilities for the applications.