Apps with 'Content Searching' feature
Listary is a revolutionary search utility for Windows
that makes finding your files and launching applications blazing fast, for casual and power users alike!.
A fast real-time search engine for displaying regular expression matches (both file name and content) across multiple directories.
Splunk is software that provides unique visibility across your entire IT infrastructure from one place in real time.
Full-text morphological search among documents and e-books of dozens of file types, including text in archives and disk images; on the your desktop, LAN, clouds (WebDAV) and removable drives.
EasyGrep is an easy to use Windows grep software which allows you to search within files on your computer. Supports text based searches as well as regex searches. Supports Notepad++.