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.
Launchy - Launchy is a cross platform app launcher that also launches documents, folders and web browser bookmarks.
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.
Ulauncher - Fast application launcher for Linux. Custom shortcuts for web URLs and scripts.