This is a category of high quality PBR Metal textures. All textures are free for commercial use.
Pitted Metal 1 PBR Material - Free PBR Materials
Scratched Metal PBR Texture
PBR-White-Metal-Cover - Good Textures
Clean Metal Texture - 3D Assets and PBR Textures - LotPixel
Metallic Magic: 90+ PBR Metal Textures for 3D Design
Golden Metal 05 PBR Texture by things
3D Textures – Free seamless PBR Textures for CG artists
50+ Free PBR Texture Sets for Unity - Unity Forum
Aluminium Texture Free Download - Free 3d textures HD
Metal Plate PBR Texture - 3DHEVEN
ArtStation - Rusty Iron Metal 3D texture PBR High Resolution Free Download 4k
3D textures PBR free Download - Iron