Every on know google Adsense is the most popular ad agency . here some of the alternatives for adsense .
Revenue hits is a Performance Ad network, which means they pay you for results (CPA which is great for many niches), however, they have CPM and CPC models too.
Adversal is a great alternative of Adsense and works as great as Chitika. They have good banners and the CTR and revenue adapts to get the best results for your website.
Propeller Ads is one of the biggest pop-under networks available. They started working on 2011 and quickly developed into one of the biggest networks with great CPMs.
PopAds is a performance network specialized in Pop Unders. They have good rates and they can monetize all countries. Something great about PopAds is that they can pay daily as long as you earn $5 or more per day.
Yllix is a network I have heard a lot in the last years that has a decent CPM and many monetization options. Their homepage might look simple but their dashboard is great and it’s easy to get started.