I used to play that Dragon Mania one. It was fun, but then it got riddled with ads which was what drove me out.

I was also addicted to Star Wars: Galaxy of Heroes. I got it when it first came out so I managed to climb the ranks quite quickly, but then actually good players began playing and I sunk down the ranks and got bored. XD

I got into Pokemon Duel but now that's worn off as well, lolol. So right now I don't really play any mobile games, except now that Go has Johto pokemon out, I may use that a little more till I get bored again. :3