I'm looking for a few example facet file types that allow applying face materials in the same file. At the moment I know of COLLADA (.dae) but I'm looking for others due to the difficulty on manually parsing and writing that I'm implementing. Other requests I have are that the file is human readable, ie ASCII vs binary. I've looked at Wavefront (.obj) formats but they require a secondary file for the face materials. I've also looked into the PLY format but that one looks focused around vertex coloring vs face coloring.
Having an open and easy to understand format is greatly appreciated.