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.
Gnome-Pie - Gnome-Pie is a circular application launcher for Linux.
Mutate - Mutate is a simple launcher inspired by ...
Slingshot launcher - Lightweight, stylish Launcher for Elementary OS
Scherlokk - Mac OS X application. Simple and user friendly, Scherlokk will find your media and missed files - quickly.