FreeCAD - An open-source parametric 3D modeler
MagicPlan - The floor plan creation app magicplan lets you create dimensioned floor plans without actively measuring or drawing. With its Augmented Reality.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
Sweet Home 3D - Sweet Home 3D is a free interior design application that helps to draw the plan of house, arrange furniture on it and visit the results in 3D.
SketchUp - 3D for Everyone
Planner 5D - Home Design Software & Interior Design Tool ONLINE for home & floor plans in 2D & 3D. Read more about Planner 5D.