Minix editline is the line editing library from Minix, originally created by Simmule R. Turner and Rich $alz in 1992. It can be linked into almost any program to provide command-line editing and history. The editline library is call-compatible with the FSF readline library, but is a fraction of the size and offers fewer features. It is distributed under a "C News-like" copyright; see the file LICENSE for details.
playerdo is a script for controlling a variety of different media players from a single command line interface. It is intended to be used with keyboard shortcuts, especially the media keys (play/pause, next, etc.) found on many keyboards. It automatically detects which media player is running and tries to do the right thing.
gcp (Goffi's CoPier) is a command line file copying tool, loosely inspired by cp, but with high level functionality like a progress indicator, the ability to continue copying multiple files even when there is a problem with one of them, and the use of a journal to track successful copying. File names can be fixed to ensure compatibility with the target filesystem. If you launch a copy operation when another is already running, the files are added to the first queue to avoid hard drive thrashing. You can keep track of files you have copied, and re-copy them later. gcp is approximately option-compatible with cp.
Autojump is a tool that acts as a complement to cd: it makes navigating your filesystem a lot faster. It works by automagically maintaining a database of the directories you use the most from the command line, and allows you to jump back and forth between them, by typing just a few letters of the name of the directory you want to jump to. It works for Linux, Mac, and Cygwin under Windows.