Gnome-Pie - Gnome-Pie is a circular application launcher for Linux.
Cairo-Dock - Cairo-Dock / GLX-Dock 3. 4 is now available. Cairo-Dock 3. 4 is finally released! One year after the 3.
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.
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.
Launchy - Launchy is a cross platform app launcher that also launches documents, folders and web browser bookmarks.
Ulauncher - Fast application launcher for Linux. Custom shortcuts for web URLs and scripts.