Convertio - File Conversion in the Cloud
regexxer - regexxer is a nifty GUI search/replace tool featuring Perl-style regular expressions.
Zamzar - Free conversion online of many type of documents (images, text, video, audio...
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, ...
CloudConvert - convert anything to anything - more than 200 different audio, video, document, ebook, archive, image, spreadsheet and presentation formats supported.
dnGREP - dnGrep allows you to search across files with easy-to-read results.