Action game wasn't much of my thing when it comes to mobile games, but I made an exception for Quadropus Rampage. The game has a good sense of humour and it has very engaging, satisfying animations that keep me smashing enemies. The developers are also hilarious, calling it "the 16th best Android game of all times" when it was ranked 16th on roundup lists.
I quite enjoyed Godus, as a casual game. It took a little while to become very slow paced, like most games end up being.
For fans of turn based / mmos, you might wanna look up Lakoo Studios, I wish there were more players at the time I was trying out their mmo game.
Finally Injustice /Batman : Arkham Origins is a lot of fun whenever I'm sitting and got nothing to do.