Keypirinha - A lightning fast and flexible keystroke launcher for Windows. No installation required (portable).

Slingscold - Slingscold is a lightweight application launcher similar to Launchpad in Mac OS X.

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.

Mutate - Mutate is a simple launcher inspired by ...

DockbarX - DockbarX is a standalone dock that groups and launches applications.

Scherlokk - Mac OS X application. Simple and user friendly, Scherlokk will find your media and missed files - quickly.