They span pretty much across every single FF ever made or announced, from Final Fantasy I to Final Fantasy XIV as well as every side game ever made like Mystic Quest, Tactics, Crisis Core, Dissidia -you name it. Some of them do have the artist's signature as part of the image, but without actually contacting the artists themselves to get permission I don't think it'd be a good idea to put them on a site. Square may not care who uses their artwork, but individual artists usually do. I'd like to think there is some sort of workaround to this when it comes to a site that is posting the art purely for the benefit of the viewing public and does not claim ownership of the material, but not being an artist I'm not sure what would be acceptable. Maybe some of the artists here could give some ideas on how best to approach the touchy subject of posting unknown fanart?