Dzen!

Cairo-Dock is an animated application launch bar for the desktop, comparable to the dock in Mac OS X or Rocket Dock (for Windows).It is compatible with Compiz-Fusion, Beryl, Compiz and Xcompmgr, but it can also run without a composite manager (using fake transparency). Cairo-Dock can run under GNOME, KDE and XFCE.

tint2 is a simple panel/taskbar unintrusive and light (memory / cpu / aestetic). We try to get virtual desktop and multi-monitor easier to use. We follow freedesktop specifications.

GnomePanel is a highly configurable launcher and taskbar for GNOME. It forms a core part of the default GNOME desktop.

PyPanel is a lightweight panel/taskbar written in Python and C for X11 window managers. It can be easily customized to match any desktop theme or taste. PyPanel works with EWMH compliant WMs (Openbox, PekWM, FVWM, etc.) and is distributed under the GNU General Public License v2.

BMPanel (bitmap panel) is a lightweight, NETWM compliant panel for X11 Window System, which contains a desktop switcher, taskbar, system tray and clock. The application is inspired by simplicity of fspanel. BMPanel has a modern look and feel, while keeping itself tiny and small.

a lightweight application launcher for Openbox, written in Python and GTK