Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Splashroad Separation Studio - Quick and Easy Color/Shape Separation
Sketch - Professional digital design for Mac.
Rasterbator - Wall art from any image
Adobe Illustrator CC - Adobe Illustrator CC is a commercial vector graphics editor.
Posterizer - The rasterbator allows you to create posters larger than a standard page, using the tiled printing method. It will rasterize any image and output files that can be printed at home and reassemble to the original image.