Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Unity - The multiplatform game creation tools for everyone.
FreeCAD - An open-source parametric 3D modeler
Godot Engine - Feature-packed 2D and 3D open source game engine.
meshmixer - meshmixer is an experimental 3D modeling tool for making 3D mashups without too much hassle.
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.