PNMixer is a simple mixer application designed to run in your system tray. It integrates nicely into desktop environments that don't have a panel that supports applets and therefore can't run a mixer applet. In particular it's been used quite a lot with fbpanel and tint2, but should run fine in any system tray.

gElemental is a GTK+ periodic table viewer that provides detailed information about chemical elements.

ResidualVM is a cross-platform 3D game interpreter which allows you to play LucasArts' Lua-based 3D adventures (provided you already have their data files):

GNOME Secure shell Tunnel Manager is a front-end to manage secure shell tunneled port redirects. A port redirect is when you use secure shell to tunnel from your machine through another machine.

Play it slowly is a piece of software to play back audio files at a different speed or pitch. It also allows you to loop over a certain part of a file.

ImageMagick is a software suite to create, edit, and compose bitmap images. It can read, convert and write images in a variety of formats (over 100) including DPX, EXR, GIF, JPEG, JPEG-2000, PDF, PhotoCD, PNG, Postscript, SVG, and TIFF. Use ImageMagick to translate, flip, mirror, rotate, scale, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and Bézier curves. All manipulations can be achieved through shell commands as well as through an X11 graphical interface (display).