Databases & Indexes are a good source of test information.  Search for the title of a particular test in almost any online database, although this will often locate articles that refer or cite a measure without providing the instrument itself. However, research studies that use  a specific instrument, scale or inventorie often appended the tool to the published article.   Descriptive or critical comments along with reliability and validity information may also be available.  Some tests may be available for purchase only. Mental Measurements Yearbook (Buros Institute) is useful for locating a appropriate instrument that is commercially available.  Sometimes an author must be contacted for permission to use a specific instrument that is unpublished.