Hey, Tim, welcome to the forum!
You won't find much discussion about M:tG around here. I used to be an avid players, but that was back around version 6 or 7 of the basic set. I even had a friend who bought his cards back when Arabian Knights was a new expansion set! But here, we pretty much stick to playing cards, custom and standard, new and vintage - even antique.
If you look hard enough, you might find a card game that's linked to Game Center, something like Hearts or Spades. There's even a chance you'll find a networked poker app. But I don't know of any particular app that would fit the bill for you. Furthermore, some apps available in the US won't be available in Poland because of things like licensing rights and so forth. But as far as straight up card game apps, the original Texas HoldEm app from Apple is actually pretty good, even all these years later - it was one of the first apps offered in the App Store when the iPhone 3G (second-generation) came out.