how about a Source/archive thread? i got the idea for this thread after that anon asked for the shark doodles from old /v/.
its pretty simple, post a description of a picture you lost or post pictures you have on your disk and you don't know the source of, anons in the thread can try to give it to you, likewise, if you know the sauce to a picture/description posted you can help other anons by giving sauce to them, in order to keep old pictures from disappearing in the nothingness of internet oblivion.
some people can identify the artist of a picture on the artstyle/coloring alone (without any signature), and sometimes a signature is too fucking blurry or messy to point to an artist, and someone else in the board might know simply from being used to seeing the signature of that artist.
don't forget to try google reverse image search and http://iqdb.harry.lu/ (for e621 reverse search when it stops being fucking broken) before asking, you might be surprised.