Finder is a module that allows Site Administrators to create search forms for their users to find various things in Drupal like nodes or users, based on specific fields and values in those objects. The forms can use widgets like autocomplete textfields, radio buttons, select lists, and checkboxes. The module is designed so that each of the things it can find, and the way in which it finds them, are all controlled by seperate modules. This allows for some very unique use-cases, as well as lets other developers create additional modules to add more features to Finder.
Below are some links to documentation about the Finder module.