Keypirinha - A lightning fast and flexible keystroke launcher for Windows. No installation required (portable).
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.
DockbarX - DockbarX is a standalone dock that groups and launches applications.
dmenu - dmenu is a dynamic menu for X, originally designed for dwm.
Listary - Listary is a revolutionary search utility for Windows
Gnome-Pie - Gnome-Pie is a circular application launcher for Linux.