PixaFlux
Substance Designer
Material Maker
Filter Forge
TextureLab
TexGraph
Substance Alchemist
TextureWorks
kdiff3
Beyond Compare
WinMerge
Meld
Araxis Merge
DiffMerge
P4Merge
Devart Code Compare
PixaFlux
kdiff3Substance Designer - Substance Designer is a node-based non-destructive application for material authoring.
Beyond Compare - Beyond Compare allows you to compare files and folders.
Material Maker - Cross-platform, procedural texture generation tool.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
Filter Forge - On the surface, Filter Forge is just a Photoshop plugin, a pack of filters that generate textures...
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.