In a nutshell, this 156 page system-neutral sourcebook appears to be an amazing resource for any number of rpgs (certainly including DCC). Factor in that it's free
in pdf form and dirt cheap
in paperback ($4.90 US!) and, well, to me that elevates it to "must have" status.The Metamorphica
by Johnstone Metzgerhttp://www.lulu.com/shop/johnstone-metzger/the-metamorphica/ebook/product-20134312.html
If your game has a need for random mutation tables and procedures for creating all sorts of mutant abominations or unnatural things, whether they are corrupt demons and unique monsters or strange aliens and new superheroes, The Metamorphica is the book for you. As a collection of biological, psychic, and supernatural mutations, all grouped into tables so results can be randomly selected using dice, this book is a system-agnostic resource for campaigns of such diverse genres as dark fantasy, four-colour comic book, post-apocalypse, modern horror, science fiction, transhumanism, and weird high fantasy. The Metamorphica contains over 650 individual mutations, all with their own descriptions; procedures for using mutations in four different campaign types; and procedures for creating aliens, demons, monsters, and mutant animals, humans, and plants.