Demostack - The no-code product demo experience platform
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Screen Guru - Take clean screenshots of any website
LaTeXDraw - LaTeXDraw is a graphical drawing editor for LaTeX.
Drama - Design, prototype and animate in a single Mac app.
Ipe - Ipe is a drawing editor for creating figures in PDF or (encapsulated) Postscript format.