deborphan finds "orphaned" packages on your system. It determines which packages have no other packages depending on their installation and shows you a list of these packages. It is most useful when finding libraries, but it can be used on packages in all sections.

cruft is a program to look over your system for anything that shouldn't be there, but is; or for anything that should be there, but isn't.

It bases most of its results on dpkg's database, as well as a list of `extra files' that can appear during the lifetime of various packages.

cruft is still in pre-release; your assistance in improving its accuracy and performance is appreciated.