DocFetcher - DocFetcher is a portable German/English open source desktop search application.
dtsearch - dtSearch - The Smart Choice for Text Retrieval since 1991.
Anytxt Desktop Search - Anytxt is Desktop Search Tool with A Powerful Full-Text Search Engine.
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.
Recoll - Recoll is a desktop full-text search tool. Recoll finds keywords inside documents as well as file names.