HeroMachine - Create your own super-hero, sci-fi, or fantasy character sketch
Unity - The multiplatform game creation tools for everyone.
Avatar Maker - Create your own avatar online
Godot Engine - Feature-packed 2D and 3D open source game engine.
The Character Creator - aims to provide a fun and easy way to help you find a look for your characters.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.