dtSearch

FileSeek is an easy-to-use file search app that includes advanced functionality for power users! Search through files using simple queries or regular expressions. You can even sync your search settings between computers. FileSeek uses multithreading technology to improve the speed of its searches, making it able to out-perform any Windows search. With no background search indexing, FileSeek will never affect the performance of your computer while closed. Improve your workload by saving your search criteria as a search profile. Save, load, or modify your most common searches to make your life easier. With FileSeek’s tabbed search interface, there is no longer any need to wait for a search to be complete before starting a new one. You can start a search in another tab without opening another window, keeping your taskbar neat and tidy. Use FileSeek’s query language or regular expressions to search for specific information inside files or folders.

Crestadoro is a networkable file indexing and search tool. You can install it on multiple Windows machines, create libraries of documents that reside on each machine, then search and access the files from anywhere on your network. You can install Crestadoro on as many machines as you like, both the indexing engine and the search client are easy to set up. You can optionally use SQL Server to store the data if you don't want to use the internal storage mechanism that comes as standard (though it is pretty wizzy!). The Community Edition is completely free to use, you can have as many libraries as you want, the only limitation is that each library can only hold a maximum of 100 documents. Crestadoro is named in honor of Andrea Crestadoro, a chap who lived a couple of hundred years ago who is generally considered to be the first person to come up with the idea of indexing a book by its content rather than its title. He was also an inventor who came up with some bonkers ideas!