AxSoft - WYSIWYG equation editor for Word and LaTeX.

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…

MathLive.js - TeX is the gold standard for typesetting of mathematical content.

MathCast - MathCast is an equation editor, an application that allows you to input mathematical equations.

LaTeX Search - A quick lookup for LaTeX code.

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.