Orbiter

Orbiter is an application launcher where you can place documents and other applications that won't fit in your Dock but that you still need to use frequently.

It can group applications by tags, simplifying how you access a bundle of similar applications. In the settings, you can make Orbiter require two clicks instead of one to open applications.

Another interesting feature in Orbiter can hide the application window after the computer remains inactive for a certain amount of time. To make it visible again just hover your cursor over a specific area on the screen.