I would love to see an online - or even a physical cards - version of Gwent. But they would have to massively expand the amount of available cards. Which is very possible, with how huge the Witcher universe is. If they did this, I would actually go back to playing a trading card game - something I haven't done since I was like, sixteen, and Magic: The Gathering started getting popular.
I mean, think about it. How many more cards could there be? Hundreds and hundreds at least. Dudu spy card, Mother Nenneke discard pick-up. I could sit here for hours thinking of them.