Extra Metal Textures.
Blue Red White and Black variations of existing (valve) metal materials.
This pack contains 25 textures, total size for the whole thing: 346 kb.
There is a slight issue though, They will not show any color in "3D Shaded Texture Polygons" cameraview in hammer. But they DO in the regular "3D Textured".
Also, they have no color in the material browser, but I have named them so you can easily find the one you want, hopefully.
The minimal impact on .bsp size is great though (few bytes for most of the textures) so don't be afraid to use them just because they have the wrong color in hammer!
Extract the zip in
Steam/steamapps/<user>/team fortress 2/tf
If you did it right there should be a bunch of files in your tf/materials/metal folder.