My friend Martinho da Gloria at Automatication has created two plug-ins that I feel are essential for any production-oriented InDesign user. You need to try these out!
Multi-Find/Change has been around for a while. This handy plug-in lets you string together and save multiple find/change queries so that you can recall them quickly and run them all at once. For example, if you find yourself frequently cleaning up imported text by searching for all multiple spaces and replacing with a single space, searching for all tabs and replacing them with nothing, searching for multiple returns and replacing them with a single return, etc., you could set up a single set containing all these queries, and run them at any time with a single command.
Find/Change Attributes is a relatively new plug-in that enables you to quickly load formatting attributes from selected text into the Find/Change dialog box. If you use the Find/Change dialog heavily, you know that you can search for not only literal text, but also text formatting. But specifying the text formatting to search for can be time-consuming. This script makes it so much easier. You just select some text with the formatting you want to search for,
Both of these plug-ins are essential for anyone doing EPUB work, working with XML data, or creating long documents. These workflows often require industrial-strength search and replace, and these plug-ins make this easy.
Multi-Find/Change is available for InDesign CS4/CS5.x/CS6, and Find/Change Attributes is available for CS5.x/CS6. You can download a trial version and the user guide, and try them out before purchasing.