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.

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

Plank is meant to be the simplest dock on the planet.

WinLaunch helps to organize and access all of your important applications and files with ease and in style.

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.

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".

XLaunchpad is a versatile application addresses to all audiences that creates shortcuts to the most used computer resources.