If you are using adsense and want to maximize your earnings by using other ad networks, here are some options that I have used and also made money.
Amazon
Infolinks
Media.net
A-Ads
Adhitz
Interestingly, you can also use these ads as adsense alternatives
Amazon
Infolinks
Media.net
A-Ads
Adhitz
Interestingly, you can also use these ads as adsense alternatives