FreeCAD - An open-source parametric 3D modeler
Unity - The multiplatform game creation tools for everyone.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Onshape - Onshape is the first full-cloud 3D CAD system. It runs in a web browser and on any mobile device.
Sculptris - Sculptris: Enter a world of digital art without barriers.