ChessDB is a free open-source chess database for Windows, Linux, Mac OSX and most UNIX and UNIX-like operating systems. ChessDB is based on code from Scid http://scid.sourceforge.net/ - a project for which there have been no updates for several years. In
surfit is an open source and free gridding and contouring software. surfit can do interpolation/approximation of points, contours and surfaces, can take fault lines and trend surfaces into account, can use inequalities and other conditions. Supports a lo
Repeater controller and EchoLink software for Linux including a GUI, Qtel - the Qt EchoLink client. The SvxLink project has now moved to GitHub. The new home page for the project is http://svxlink.org/ .
Core library for multiplatform Application Development Framework used in various projects: Vehicle monitoring, SMS sender application and others. Includes builtin features like XML, scripting, translation, etc.
ChemVisio is software which might be useful for educational purposes (non-organic chemistry, crystallography etc.). It might be a good visualization support for all people who need better illustrations than that you could see in books.
Lightweight, modern, flexible and well-customisable cross-platform multi-protocol instant messaging client
Lamia or Lamia Engine is the modern generation free distributable and open source game engine for creating computer games for several prevailing software platforms and very maybe hardware platforms either.
LinuxCNC controls CNC machines. It can drive milling machines, lathes, 3d printers, laser cutters, plasma cutters, robot arms, hexapods, and more.
Scripting Tcl interface to Qt multiplatform library