TextureLab - Free, Cross-Platform, GPU-Accelerated Procedural Texture Generator.
Unity - The multiplatform game creation tools for everyone.
NeoTextureEdit - NeoTextureEdit is an open source (GNU LGPL v.
Godot Engine - Feature-packed 2D and 3D open source game engine.
GraphicDesignerToolbox - Graphics editor for composing textures, buttons, logos, icons.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.