7stacks helps you group icons into stacks on your Windows 7 taskbar.

Cairo-Dock is a desktop interface that takes the shape of docks, desklets, panel, etc.

Dock is UI widget for MacOS.

GNOME Panel is a highly configurable launcher and taskbar for GNOME. It formed a core part of the GNOME desktop in versions 1.x and 2.x. It has been replaced …

Nimi Places organizes desktop into customizable containers, displaying files and folders from chosen locations as icons and thumbnails.

RocketDock is an application launcher.

Avant Window Navigator (AWN or Awn) is a dock-like bar for Linux, which sits on an edge of a user's screen and tracks open windows.

Circle Dock is a circular, oval, and spiral dock for Windows.

Docky is a full fledged dock application that makes opening common applications and managing windows easier and quicker.

Winstep Nexus Dock is a free professional dock for Windows. With Nexus, your most frequently used applications are only a mouse click away.

ObjectDock is a dock similar to that in the Aqua GUI. It is distributed by Stardock for Windows.

tint2 is a system panel/taskbar for Linux. It is described by its developers as "simple, unobtrusive and light".