I just looked through them all and was overwhelmed by the sheer volume of fantastic art. Really nice collection you've made there.
I'm not sure that I could choose just one picture as my favourite. I like this picture that shows many characters together in one picture:
Regarding "lost art" being put on Panzer Dragoon Legacy, that does sound reasonable if the image is definitely not available anywhere else. This site exists to preserve, after all, and we run the risk of losing the art otherwise. I'm not sure what the best way to go about this is. Perhaps we set up a special contributor profile for mystery artists, e.g. "The Lost Artists". But we would have to try and avoid cases where the artist contacts us and complains that the picture was added without their consent. Is there a way to do an image search across the web (e.g. comparing files) to see the image is already hosted elsewhere?