FreeCAD - An open-source parametric 3D modeler
Time and Material Plus - Time and Material Plus is a software program designed to process billable data and deliver transparent billing results.
SketchUp - 3D for Everyone
Esti-Mate Software Version 4.5 - Esti-Mate Software is a program for residential construction building that converts takeoff dimensions from blueprints to an itemized list of waste factored delivery order quantities.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
Assemble Insight - Construction Estimating Software and BIM and Architectural Design Software