PBR Metal Textures is a collection of 32 Gloss Textures consisting of variations of Scratched Metal Surfaces, as well as 7 demo scenes. All textures tile, are PBR-calibrated and have values based on real world surfaces.
All textures have a resolution of 2048x2048, uncompressed, and they come both in grayscale gloss maps as well as compiled spec+alpha gloss maps and their materials if you just want to drag-and-drop them in your project. In addition, these textures work perfectly with other PBR-texturing software. They're Substance and Surforge-tested!
At a very affordable price tag, this collection is the best bang-for-buck available when it comes down to quality metal textures.