GNU Astronomy Utilities (Gnuastro) is a collection of programs (the `gnuastro' package) and librarires (this package along with `libgnuastro-dev') for astronomical data analysis and manipulation. The programs can be run on the command-line for efficient and easy usage and the libraries can be used within C and C++ programs.

Muffin is a window manager performing compositing as well based on GTK+ and Clutter and used in Cinnamon desktop environment.

Open CASCADE Technology is a suite for 3D surface and solid modeling, visualization, data exchange and rapid application development. It is an excellent platform for development of numerical simulation software including CAD/CAM/CAE, AEC and GIS, as well as PDM applications.

A free cross-platform library of fast C++ routines for plotting data in up to 3 dimensions. It can export plots to bitmaps and vector EPS, SVG, IDTF files. There are simple window interfaces based on GLUT, FLTK and/or Qt. MathGL can also be used in the console. There are interfaces to a set of languages, such as, C, Fortran, Pascal, Forth, Python, Octave.

A free cross-platform library of fast C++ routines for plotting data in up to 3 dimensions. It can export plots to bitmaps and vector EPS, SVG, IDTF files. There are simple window interfaces based on GLUT, FLTK and/or Qt. MathGL can also be used in the console. There are interfaces to a set of languages, such as, C, Fortran, Pascal, Forth, Python, Octave.

elan is a small tool for managing your installations of the Lean theorem prover. It places lean and leanpkg binaries in your PATH that automatically select and, if necessary, download the Lean version described in the lean_version field of your project's leanpkg.toml. You can also install, select, run, and uninstall Lean versions manually using the commands of the elan executable.