potrace - Open source program that transforms bitmaps into vector graphics.
Unity - The multiplatform game creation tools for everyone.
Vector Magic - Easily convert JPG, PNG, BMP, GIF bitmap images to SVG, EPS, PDF, AI, DXF vector images with real full-color tracing, online or using the desktop app!
Godot Engine - Feature-packed 2D and 3D open source game engine.
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.