This chart allows you to understand what creative types are being used by the selected advertisers and how budget is distributed between them.
Values like Banner and Native are simply the ad type. At the same time, with more versatile formats like interstitial and Rewarded Video, the ad type is followed by what's inside the container like: HTML, Video, Playable and sometimes Unknown. The combination might look like: Interstitial-video, Rewarded-playable, ... Note that Rewarded-video with interactive end card will appear as Rewarded-playable.