CLaunch - You are free to choose double-click on the desktop and move mouse to the corner of the screen, such...
DockbarX - DockbarX is a standalone dock that groups and launches applications.
MaxLauncher - A simple tabbed application launcher.
Synapse - Synapse is a semantic launcher written in Vala that you can use to start applications as well as find and access relevant documents and files by making use of the Zeitgeist engine.
RocketDock - RocketDock is a Mac OS X dock clone.
Gnome Do - Simple, sleek, swift, smart. Do. GNOME Do allows you to quickly search for many items present on your desktop or the web, and perform useful actions on those items. GNOME Do is inspired by Quicksilver & GNOME Launch Box.