Pepakura Designer - Pepakura Designer allows you to easily create papercraft models from 3D data you create from your...
FreeCAD - An open-source parametric 3D modeler
Ultimate Papercraft 3D - Ultimate Papercraft 3D is a standalone software for creating papercraft from 3D models.
SketchUp - 3D for Everyone
Ultimate Unwrap 3D - Ultimate Unwrap 3D is a standalone UV mapping software for unfolding and unwrapping 3D models.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.