Niches With Most Relevant Ads

CTR is one of the more important factors in CPC (Cost Per Click) programs. Although, for many webmasters, CPC programs don't work as well as other monetization programs but for many they do. I am looking forward to increase my earnings with google adsense (one of the best CPC programs). So I thought this time I would go for a niche which has most relevant ads.Relevant ads would simply result in more clicks and thus more revenue. But when I tried to research on this topic through search engines. all of them including google, bing, yahoo, duckduckgo failed to bring relevant results to me. As I don't have enough time to personally go to different websites and search for the topic within each, I thought I would rather post an entry on Xisto forum. the best online forum in my opinion.So anybody who knows something about the niche having most relevand ads is welcome to post here.I would also appreciate if someone teach me how to search for topics like these. They don't seem to be hot trends and that's why there isn't enough material out there. But still there must be some and all the famous search engines cannot bring it forward.I am looking forward for your replies.