Grace is a WYSIWYG 2D plotting tool for the X Window System and M*tif. Grace runs on practically any version of Unix-like OS. As well, it has been successfully ported to VMS, OS/2, and Win9*/NT/2000/XP (some minor functionality may be missing, though).
Veusz is a GUI scientific plotting and graphing package. It is designed to produce publication-ready Postscript or PDF output. SVG, EMF and bitmap formats export are also supported. The program runs under Unix/Linux, Windows or Mac OS X, and binaries are provided. Data can be read from text, CSV or FITS files, and data can be manipulated or examined from within the application.
Veusz is a scientific plotting and graphing package written in Python. It uses PyQt (Wiki) and Numpy. Veusz is designed to produce publication-ready Postscript/PDF output. Veusz runs under Unix/Linux, Windows and Mac OS X.
xd3d is a simple scientific visualization tool designed to be easy to learn. It can plot 2d and 3d meshes, with shadowing, contour plots, vector fields, iso-contour (3d), as well as 3d surfaces z=f(x,y) defined by an algebraic expression or a cloud of points. It generates high quality vector PostScript files for scientific publications and still or animated bitmap images. It includes the graph plotter xgraphic.