Используйте приложение APKPure
Историческую версию Mobile Ads Example: Interstitial +Banner + Video можно получить на Android
aDsample образца App, который содержит все общие формы объявления с исходным кодом !!
DOWNLOAD THE APP "MOBILE ADS EXAMPLE NEW" WITH BETTER FEATURES!
This app shows all common typs of mobile ads – such as the BANNER AD, the INTERSTITIAL AD, the REWARDED VIDEO AD + it shows how to implement an AD-LISTENER and an AD-WRAPPER. All of this together with the SOURCE CODE, the neccessary NUGET PACKAGES + DETAILED EXPLANATIONS and EXAMPLES in C# for XAMARIN.
You may as well buy the whole solution as a project inside this app for only 4.99$.