LibreOffice - Math - Math, LibreOffice, math editor, ODF, OpenFormula, open standards
Edtr.io - Intuitive WYSIWYG web editor, open source & fully adaptable.
Math Magic - MathMagic Equation Editor for Desktop Publishing software & Word Processors, Adobe InDesign, QuarkXPress, MS Word, iWork, for Technical writing with very easy interface and fast input.
TinyMCE - TinyMCE is a content editor that functions as a plug-in for Wordpress websites.
KLatexFormula - KLatexFormula is an easy-to-use graphical application for generating images (that you can drag and...
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.