ripgrep - ripgrep combines the usability of The Silver Searcher with the raw speed of grep.
grepWin - grepWin is a simple search and replace tool which can use PCRE regular expressions to search for...
ack - Ack is designed as a standalone (one perl file) replacement for 99% of the uses of grep.
DocFetcher - DocFetcher is a portable German/English open source desktop search application.
The Silver Searcher - A code searching tool similar to ack, with a focus on speed.
dnGREP - dnGrep allows you to search across files with easy-to-read results.