GIMP - GIMP is a multiplatform photo manipulation tool.
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Sketch - Professional digital design for Mac.
Adobe Illustrator CC - Adobe Illustrator CC is a commercial vector graphics editor.
Free Visio Viewer - Free Visio Viewer is a free Visio file viewer for the Windows, Mac OS X, and Linux operating systems.
Adobe Illustrator - Adobe Illustrator is a vector graphics editor.