It's pretty obvious and normal that you are interested in campaigns that are past the testing phase and are already profitable.
Basic tips on searching
1) Don't restrict yourself from monitoring other GEOs as well
Who says that it wouldn't work if you take certain style/design from X country, swap text/ translations and run it in Y country?
2) Don't restrict yourself from monitoring other offers/products in same vertical/niche
If banner and/or landing page works for X app install offer, who says it won't for Y app?
3) Don't restrict yourself from monitoring other traffic types
AdPlexity is the only tool that supports popups, mobile web and in-app ads under one roof.
Who says it wouldn't work if you take LP that is running on in-app and try it on popups?