I like the idea of Schools of Type. There are three major schools: Jungian, MBTI, and Keirsey. But there are others, and of course variations within the schools. Here are some I'm acquainted with, along with their web sites. Many of these have further links.
Another Way of Looking at Psychological Types
Type Organizations
Association for Psychological Type. http://www.aptcentral.org/
Australian Association for Psychological Type. http://www.aapt.org.au/
Jungian
Benzinger Thinking Styles Assessment. http://www.benziger.org/
High Performing Systems. http://www.hpsys.com/
The Jung Index. http://www.jungindex.net/
C.G. Jung Institute of Boston. http://www.cgjungboston.com/
MBTI
16Types.com
Center for the Applications of Psychological Type. http://www.capt.org/
Consulting Psychologists Press. http://www.cpp-db.com/
HumanMetrics. http://www.humanmetrics.com/index.htm
Institute for Type Development. http://www.itd.net.au/
Otto Kroeger Associates. http://www.typetalk.com/
PersonalityType.com. http://www.personalitytype.com/
PersonalValuation.com http://www.personalvaluation.com/
Psychometrics. http://www.psychometrics.com/
Team Technology. http://www.teamtechnology.co.uk/
Type Logic. http://www.typelogic.com/
Type Resources. http://www.type-resources.com/
Keirsey
Keirsey.com. http://www.keirsey.com/
Interstrength Associates. http://www.tri-network.com/
Other, General, Academic
The Personality Project (academic).
http://www.personality-project.org/
Big Five
Twin Study, but anyone can use it for comparison with others. http://www.outofservice.com/twins/
A Light Look at Psychological Type