Substance Designer - Substance Designer is a node-based non-destructive application for material authoring.
Material Maker - Cross-platform, procedural texture generation tool.
TexGraph - Node-based, procedural texture creation tool for Windows.
NeoTextureEdit - NeoTextureEdit is an open source (GNU LGPL v.
DarkTree - DarkTree 2.5 is an advanced procedural shader authoring tool.
TextureLab - Free, Cross-Platform, GPU-Accelerated Procedural Texture Generator.