Material Maker - Cross-platform, procedural texture generation tool.
NeoTextureEdit - NeoTextureEdit is an open source (GNU LGPL v.
TextureLab - Free, Cross-Platform, GPU-Accelerated Procedural Texture Generator.
Rectitude - Procedural generation pixel art editor.
PixPlant - A complete solution for repeating textures and 3D maps. Save a lot of texturing time with PixPlant!
Substance Designer - Substance Designer is a node-based non-destructive application for material authoring.