There were five ad networks highly focused on games - Chartboost, Unity, Adcolony, ironSource, and Vungle - each of them has more than 90% share of voice for mobile games (iOS).
Video is still the most popular format in mobile games with >50% share from all creatives.
Puzzles are responsible for lion's share of all UA. The genre is at first place in Chartboost, Adcolony, Unity, Vungle, ironSource, MoPub, Facebook, and AdMob.
4 US Creatives trends:
Fake Playable Ads.
Relaxing music videos.
Playable Ads for Mid-Core games.
Real-World conversations videos.