Everything by Voidtools - Everything. Locate files and folders by name instantly. Everything. Small installation file. Clean and simple user interface.

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

DocFetcher - DocFetcher is a portable German/English open source desktop search application.

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.

dnGREP - dnGrep allows you to search across files with easy-to-read results.

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.