PyRPM is an experimental project to look at RPM package management. It is a Python module and a collection of scripts that provide similar functionality as rpm, yum, and related software. It mainly deals with RPM packages, the RPM database in /var/lib/rpm, comps.xml files, and yum repositories (called repo data).
cerbeRun is a software runner. The applications are stored inside a .tar (version 0.3 will use the ISO9660 format) file renamed with the extension .run. cerbeRun's format allows you to switch between different architectures using an .xml file, in which are specified different rules for different archictures. This is all done in user space without root access.
Paludis is a package manager for Gentoo (and derived distributions) and Exherbo. It consists of a core library and a number of console-based clients. Package formats supported include Gentoo ebuilds and kdebuilds (as defined by the Package Manager Specification), the Exherbo exheres-0 format, and various miscellaneous utility pseudo-formats for managing accounts, unwritten and unavailable packages, and packages for which no package exists.
NUU (Network Update Utility) is a GUI RPM package manager based on Yum that supports downloading, installation, and updating of packages from remote repositories, and removal of installed packages. It has the ability to examine both installed and available packages, and includes a repository configuration editor. It also supports package groups and suites of packages. Finally, it recognizes a simple authentication mechanism called buffet based on a server-side cgi-bin program.
SoftwareUpdate is a Java class that assists with adding an automatic software-update feature to applications. It doesn't perform the update, but takes care of administrative stuff like looking up the version number of the latest version, with the ability to distinguish and check different places based on operating system. It also builds the OS-specific URLs to make it easy to do a quick latest-version check in any desktop or server application.
DeltaRPM is a tool that generates RPMs that contains the difference between an old and a new version of an RPM. This makes it possible to recreate the new RPM from the deltarpm and the old one. You don't have to have a copy of the old RPM, as it can also work with installed RPMs. The package also contains tools for creating and applying delta ISOs.