Listary - Listary is a revolutionary search utility for Windows
Everything by Voidtools - Everything. Locate files and folders by name instantly. Everything. Small installation file. Clean and simple user interface.
Keypirinha - A lightning fast and flexible keystroke launcher for Windows. No installation required (portable).
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.
Agent Ransack - Agent Ransack is a tool for finding files and information on your hard drive fast and efficiently.