I have Pokemon Shuffle on iOS and it's much more frustrating at times than the 3DS version (harder to grind in-game currency, harder catch rates, have to be online to play = more prone to needing microtransactions, though I've cleared 149 stages so far without having to do so). Still, it does have its charm as well (Facebook integration to let you send lives to friends). Right now, I'm hoping to get the Charizard Mega Stone in the ongoing competition (only the top 250,000 worldwide will get it in Shuffle Mobile).
I also have Bar Oasis and its sequels on it, even though they're a bit old - charming visual novels with bartending on the side (I realized how addicted I was when I just started playing it and didn't mind that people were looking at me weirdly for shaking my phone (to mix drinks in the game).