Tests/instruments/scales allow you to measure outcomes.
Reviews of tests are available through the Mental Measurements Yearbook. If there isn't a review of the test you're looking for, search for the name of the test in Google Scholar to find the article it was originally published in. That article will give you all the information about the development of the test.
PsycTESTS contain the full-text of some tests, instruments & scales.
Tests are copyrighted. If you cannot find the full-text of the test via databases, journal articles and PsycTESTS, you may have to purchase the test directly from the publisher.
Sometimes you can view a test because it has been published in a journal article or dissertation.