I heard Hearthstone was made in Unity 3d, so my question goes, the cards, are they prefabs for gameobjects, or ex. GUI.Box?
they are prefab
http://forum.unity3d.com/threads/blizzards-hearthstone-made-with-unity.175107/page-2#post-1820576
I can pretty much promise you they won’t be using GUI.Box… 
Most likely something like Scaleform, but that’s just a guess (as will be any other reply you receive on here).
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