Aptitude and ability tests
Personality tests
Prospects:
Really useful summary of psychometric tests and lots of useful links.
http://www.prospects.ac.uk/cms/ShowPage/Home_page/Applications__CVs_and_interviews/Tests_and_exercises/Psychometric_tests/p!eLagFgF
Target Jobs:
Links to section on psychometric tests which has a lot of resources on why tests are used, the different types of tests and some examples.
http://targetjobs.co.uk/job-hunting-tools/psychometric-tests.aspx