Search Files from Internet, Educational & Library Resources and more. findthatfile was founded in 2009 and has grown to become the "most extensive file search on the Internet". Common searches are for PDFs, Documents, Excel, Powerpoint, Audio, Video, RAR and ZIP compressed files, Fonts, and much much more. They go on to say: "We search as deeply as possible to identify the most relevant data from over 300 million files. This means we open each file, identify its author, title, contents, text extracts and all kinds of goodies that nobody else does.We also search more places than anyone else including 47 file types and 558+ file extensions including over 70 million domains."
You can try it out here:
find that file
the largest file/media search engine on the Internet