In AE Tutorial – Super-quick carbon fibre effect, Shortformvideo shows you "how you can create a realistic carbon fibre texture in After Effects using Ramp and CC RepeTile. It takes a few seconds to create, and works really well in high-tech or motoring videos. You can also download the project file..."
Shortformvideo also posted a video of a classic technique that combines blur, noise and time control settings to create a brushed metal effect.
Update: also check out Deke’s Techniques #4: Creating a hammered metal background,