LEGO Digital Designer Official app for creating 3D models with LEGO blocks for design of complex models and art with access to the most popular and obscure blocks made by the Danish company.
LibreCAD Easily create and edit various types of CAD files for free -- 2D PPM, XBM and XPM formats included.
Mini CAD Viewer Viewing and zooming in of DWG, DWF and SXF CAD files.