A free cross-platform library of fast C++ routines for the plotting of up to 3-ranged data. It can export to bitmap and vector EPS/SVG files. There are window interfaces (GLUT/FLTK/Qt) and console tools. MathGL can be used from C/Fortran/Python/Octav/Lua
Gabedit is a Graphical User Interface for FireFly (PC-Gamess), Gamess-US, Gaussian, Molcas, Molpro, MPQC, NWChem, OpenMopac, Orca, PSI4 and Q-Chem computational chemistry packages.