dtsearch - dtSearch - The Smart Choice for Text Retrieval since 1991.
SwiftSearch - SwiftSearch is a lightweight program whose purpose is to help you quickly find the files you need...
DocFetcher - DocFetcher is a portable German/English open source desktop search application.
Everything by Voidtools - Everything. Locate files and folders by name instantly. Everything. Small installation file. Clean and simple user interface.
SearchMyFiles - Alternative to the standard Search For Files And Folders module of Windows. Duplicates search is also supported.
Agent Ransack - Agent Ransack is a tool for finding files and information on your hard drive fast and efficiently.