Here are more creative formats and features you can use for mobile apps.
The Google Mobile Ads SDK can't implement Google Publisher Tag (GPT) passback. The use of GPT passbacks in third-party creatives isn't a valid workaround, since all in-app ad requests should be made through the SDK.
If your current demand sources can't fill all of the ad requests they receive, you should implement a yield group to try and optimize and improve fill rate.
MRAID is an industry standard API for rich media ads running in mobile apps. It enables the creative to perform several built-in actions such as expand to full screen. With Google Ad Manager, you can target specifically for MRAID v1 or MRAID v2. Learn more about MRAID.
With mobile creatives, you can interact with the users’ mobile device, triggering actions and applications for an enhanced user experience. This allows for various creative destinations such as link to app store and phone calls.
You can serve higher density versions of creatives to mobile devices that have high density displays. Use the “Density” dropdown when creating the line item and select 1.5x density or 2x density as needed.
Optimize creatives for multiple screen sizes
Google Ad Manager doesn't resize creative assets. For example, Google Ad Manager wouldn't enlarge a 320x50 creative to fit in a 350x50 slot.
Use Adaptive Banners to automatically pick the best ad slot size (the space reserved for creatives) for the device in use. Smart Banners are another option. However, because Smart Banners only fill screen width, they aren't as flexible as Adaptive Banners and may not perform as well.