DocFetcher - DocFetcher is a portable German/English open source desktop search application.
Everything - Everything. Locate files and folders by name instantly. Everything. Small installation file. Clean and simple user interface.
Agent Ransack - Agent Ransack is a tool for finding files and information on your hard drive fast and efficiently.
FSearch - A fast file search utility for GNU/Linux based on GTK+3
Recoll - Recoll is a desktop full-text search tool. Recoll finds keywords inside documents as well as file names.
SearchMyFiles - Alternative to the standard Search For Files And Folders module of Windows. Duplicates search is also supported.