I do not believe that there is a rule in the game that prevents me, when I am shuffling, looking (and even counting) the sorts of cards that I have. Would it be possible to add a feature where I can see what all I currently have in my deck? I am thinking that when I hover over my name (where I would normally see the cards I have in exile, set aside, etc.), I would see a current deck inventory. This would be helpful in many, many instances. Granted, I should not have access to that information for other players.