This program supports a lot of different .PAKs, also includes HyperRipper (scan unsupported .PAKs to look for resources)
https://www.elberethzone.net/dragon-unpacker.html
Java based, very good .PAK extractor
http://www.watto.org/game_extractor.html
Find other here:
http://wiki.xentax.com/index.php/Extraction_tools