LibreOffice - Math - Math, LibreOffice, math editor, ODF, OpenFormula, open standards
Okular - Okular is a universal document viewer based developed by KDE.
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.
Sumatra PDF - Sumatra PDF is a slim PDF/DjVu/EPUB/XPS/CHM/CBR/CBZ/MOBI viewer for Windows.
KLatexFormula - KLatexFormula is an easy-to-use graphical application for generating images (that you can drag and...
Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.