Ask HN:How do I find market info databases?

I am trying to compile a list of Real Estate Boards and some other market data. I am sure that a list like this has been compiled before. Is there a free or paid resource that I can use to look up this kind of market data?

A month or two ago I saw a post on HN that had sources of information databases, but I unfortunately cannot find it anymore...

Edit: Found the referenced HN post here: http://news.ycombinator.com/item?id=1493768