Material Maker - Cross-platform, procedural texture generation tool.
Substance Designer - Substance Designer is a node-based non-destructive application for material authoring.
Filter Forge - On the surface, Filter Forge is just a Photoshop plugin, a pack of filters that generate textures...
PixaFlux - PixaFlux is a node based image processing application.
JSplacement - JSplacement is a cross-platform pseudo-random 8K displacement map generator written in HTML and JS.
Substance Alchemist - The material enthusiast's toolbox