I am actually pretty bad at these, and when I try to think one up, it gets used in another puzzle. I think this one is unique enough. I could be wrong.
What is missing from this set:
Spy
Rabble
Swindler
Scrying Pool
Jester
This might be too easy for honorable mentions. In case it's needed, here are the "almosts": Fortune Teller, Saboteur
And I'm going to be a spoilsport. I'm kind of bad at coming back to the forum, and I don't want to leave the puzzle wide open if that happens.
So, there is a spoiler below. I'll break it up into multiple spoiler tags in case you accidentally do mouse over it.
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The correct answer is: Sea Hag
The criteria are: Cards that make you pull from your deck an odd number of cards during someone else's turn, which you cannot use on your next turn.
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