AdTargeting is a free ad targeting and analytic tool which can help you discover more hidden interests and the most cost-effective Google keywords to effectively control ad costs and increase ROI of your ads.
InterestExplorer is a smart application to discover interests that you can target on Facebook, but that are hidden in the Facebook Ads Manager (which only shows 25 interest suggestions).
interestinsights will find you thousands of Facebook™ interests that you can target in your campaigns and reduce costs to reach a more relevant audience.