From here you can find all important The Prodigy special releases. Some of them are official but usually they are unofficial releases or made up by bootleggers! They are usually different kind of box sets or unofficial compilations. Although they might be unofficial some of them can be found from Amazon.
Usually most of the official special releases come from Japan because it is one of the largest music markets in the world. However, domestic pressings are more expensive there than in the U.S. or Europe, so Japanese labels often arrange for additional content in the locally manufactured products as a marketing technique in an attempt to be competitive with imports.
If you have or you know some other specials. Official or unnofficial ones, please mail to me them!