Dpsyco is a automated system to distribute system configurations to several computers. It is written mainly for the Debian distribution but should be portable (without too much difficulties) to other distributions or Unixes as well. It consists of a number of shell scripts to perform the desired actions. With it you can handle users, add ssh-public-keys, patch the system, update things using cfengine, install files (overriding other package files), and more.
footprint is a tool that makes it easier to create and manage kickstart files. It allows you to define systems, create profiles for systems, and macros per distribution. It can create kickstart files on the fly, make custom initrd (ramdisks), create custom bootfloppies, and can manage your DHCP and PXE configuration.
Slackpkg is an automated package-management tool for Slackware Linux. It can do tasks such as automatic downloading and installing or upgrading, browse the MANIFEST.gz (Slackware package-contents guide), and more. Dependencies are not automatically handled. It is not a replacement for pkgtool, but a valuable add-on.