Openoffice

Homepage: http://www.openoffice.org

Download link: http://download.openoffice.org/index.html

Operating Systems: Windows, Linux, Solaris, Mac

Description:The most complete and stable free office suite. With text editer, speadsheet, presentations, database and drwaing software. Recommended

OxygenOffice Professional

Homepage: http://sourceforge.net/projects/ooop

Download link: http://sourceforge.net/project/showfiles.php?group_id=170021

Operating Systems: Windows

Description: Based on Openoffice with more templates, clipart, samples, fonts and with vba support.

Libre Office

Homepage: https://www.libreoffice.org/

Download link: https://www.libreoffice.org/download/libreoffice-fresh/

Operating Systems: Windows,

Description: Probably the best