Best Facebook Methods?

I know my way around Facebook ad basics. What I've been wondering is what tools are there for finding pages and groups by their total likes or comments? What about finding keyword trends on Facebook? I'm trying to find the most active groups in certain obscure niches. What advice or tools do you guys have?

Thanks ahead of time

You can use the facebook search tool, it has recently been updated and now it can do many of the things you are asking.

Yeah, I've been playing around with it. Doing some more up to date tutorials too. Thanks