[Collect Equity]

I'm still fairly new to this board, so if my question has already been asked, please just point me to the right thread.

In reading auction magazines they claim every card to be 'rare.' But obviously not everything marked as rare would qualify. So for sake of argument, let's say that the definition of rare is a card would have a dozen or less total cards in existence.

My question is, what individual cards, sets or variations of pre-war cards would fall into the category of having 12 cards or less total in existence. To help focus the conversation, let's only focus on cards made after 1900 and only of active major league players or hall of fame player's minor league cards.

So, in everyone's opinion what cards and sets would be included in this survey?

Thanks in advance!