Mental Measurements with Tests in Print is a database that outlines the scope, focus, cost and access options for validated test instruments. It does not have the full text of tests. Most of the tests included have a fee associated with them, but they have all been validated.
If you know the name of a survey or test instrument, you can search by name for a review. However, if you don't know the name, these are the two the most effective way I've found to search:
Option 1:
Search with broad terminology for the topic or population you're interested in researching such as self-regulation, achievement, preschool, etc.
Option 2:
Choose a test category from the limiting section of the search screen to see all tests in that group