One of the sources we can use is http://diablo.somepage.com/popular/witch-doctor#builds
However, that's not good enough. Some build, for example, it is awesome for some set items and total junk for other set items. Haunt and Locust Farm are definetly needed for the Jade Harvester build but is not so useful on Helltooth builds.
Say I want to know who are the top players and what do they use? How do I find that?