On the rare occasions when I've been given a RPG-themed gift, it was nearly always a gift card for a store that sells gaming goods. The few exceptions to that have been from fellow gamers, usually minis or a good boardgame.
And that's what I tend to give if giving a gaming gift.
Never, ever buy somebody a gift in their hobby unless you know EXACTLY what item they need or want. Otherwise, you will end up buying them a cheaper version of the thing they really wanted, or some oddball item they never would have wanted.
When somebody has a hobby, odds are good they already bought the items they really want.