Material Maker - Cross-platform, procedural texture generation tool.
Unity - The multiplatform game creation tools for everyone.
Substance Designer - Substance Designer is a node-based non-destructive application for material authoring.
Godot Engine - Feature-packed 2D and 3D open source game engine.
TextureLab - Free, Cross-Platform, GPU-Accelerated Procedural Texture Generator.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.