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While not every deck is going to want to play The One Ring, it was enough that it was slowly and steadily overtaking plenty of other cards in the format
The problem is no one is going to give you $0.25 for your Loch Dragon or Trail of Crumbs, so it is very important to only include commons and uncommons that have real value, rather than just including all of them at retail price
If it's returned to its owner's hand, it'll return to its owner's hand, and so on
I have seen Kaalia decks that focus on just one of the three tribes, and that is a fun restriction
These are in Play and Collector Boosters, available in non-foil, traditional foil, and surge foil versions