DocFetcher - DocFetcher is a portable German/English open source desktop search application.
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).
Recoll - Recoll is a desktop full-text search tool. Recoll finds keywords inside documents as well as file names.
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.