Spack is a standalone package manager with its own CPIO-based package format but aiming to keep total compatibility with Slackware Linux. Written in POSIX shell as much as it makes sense, it attempts to provide a fairly complete toolkit to build, install, remove, list, retrieve, and arrange your packages. It can be used as an alternative to Slackware's pkgtools, just to independently and properly manage your local software on any distribution, or as the main package manager of the distribution you build yourself.
Payload Delivery Vehicle (PDV) is a program that builds an executable that contains a complete package (e.g. and RPM, System V package or tar file) and the commands required to install it. When the executable is run it will extract the payload (the package) and then execute another command (such as rpm -i, pkgadd -d etc.). The big advantage to this is that a developer can hand a user a single file to be executed - the end user does not need to know how to extract the package or get it installed.
AutoRPM is a program that can do any combination of the following: mirror RPMs from an FTP site, keep installed RPMs consistent with an FTP site or local directory and keep installed RPMs in a cluster or network of systems consistent. It is highly flexible and contains a fully command-line driven interactive install mode (for installing RPMs from the queue or for installing RPMs from your system interactively). It also handles recursive dependencies, multiple versions of the same RPM, the same RPM with multiple architectures, and more. It does some of the same tasks as up2date and AutoUpdate.