ripgrep - ripgrep combines the usability of The Silver Searcher with the raw speed of grep.
dnGREP - dnGrep allows you to search across files with easy-to-read results.
AstroGrep - AstroGrep is A Microsoft Windows GUI File Searching (grep) utility.
PowerGREP - Quickly search through large numbers of files on your PC or network using powerful text patterns to find exactly the information you want. Search and replace with plain text or regular expressions to maintain web sites, source code, reports, ...
grep - grep is a command-line utility for searching plain-text data sets for lines matching a regular...
The Silver Searcher - A code searching tool similar to ack, with a focus on speed.