This one came as a surprise. Not because it's Dragon Ball Z, but because it looks like a simple match-the-tiles game. But don't be fooled, Dragon Ball Z Dokkan Battle is a very complex mobile game. There's far more strategy to it than "match the blue orbs with blue characters".
There's a map to traverse across with tiles that do different things, kind of like a board game. Then there are battles where the player must find what orbs will do the most damage with any of the characters, play the orbs in order, and then take the enemy's color type into consideration as well, as certain colors are weaker or stronger against others. (It's a bit like Pokemon types.)
Collecting different characters and items and training your party are all part of the strategy as well. While the actual battles are simple to execute, mastering them takes actual strategy -- something absolutely not apparent at first glance.
Dragon Ball Z Dokkan Battle snuck its way to the top of this genre with the beneath-the-surface depth it hides. It's available on both Android and iOS and is guaranteed to get many hours out of fans of strategy.