For me it's Granblue Fantasy~ It's also the game that I've been playing longest now xD I drop most mobile games after a month or two. Though I've been playing Pocket Camp for a really long time now as well ^^ One of the things I like about GBF is that they take the gender you choose into consideration (most of the time), where in most games they'll always use 'he' to refer to the player, and that upsets me as a female player ):
Here's their logo because I think it looks pretty :