Unity - The multiplatform game creation tools for everyone.
HTTrack - HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility.
Godot Engine - Feature-packed 2D and 3D open source game engine.
WebCopy - Cyotek WebCopy is a free tool for copying full or partial websites locally onto your harddisk for offline viewing.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
SiteSucker - SiteSucker is a Macintosh application that automatically downloads Web sites from the Internet.