Some more openPBR example mtlx file that support texture maps?

as we could saw in the standard surface example, it provide a complete examples set that include how texture maps were used. but in openPBR's examples, only a few basic ones were included. i spend some time to try how it work but still not sure how do i get it correct. it would be really nice to include those example if its possible. thanks

Review the existing OpenPBR example .mtlx files and compare them with the standard surface examples that demonstrate texture maps. Identify which texture-map cases are missing, add corresponding examples, and verify that the files show correct OpenPBR texture-map usage.

Written by the indexing model from the issue text.