Edtr.io - Intuitive WYSIWYG web editor, open source & fully adaptable.
Wireflow - Create beautiful flowcharts
TinyMCE - TinyMCE is a content editor that functions as a plug-in for Wordpress websites.
Vexlio - Instantly create precise, beautiful diagrams
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…
Zen Flowchart - The simplest tool to create flowcharts