When people think of trading cards, they naturally think of baseball cards, football cards, etc. I collect trading cards for things other than sports. Unsurprisingly, these are known as "non-sport" trading cards. The cards feature things like movies, TV shows, art, etc.
Well, my collection is a very small and defined niche of non-sport trading cards. I collect the promotional cards for these various sets. A promo card is just that; it's a card (or small set of cards) used to promote a set of cards that will soon be released. These promo cards are distributed through various means such as hobby shows, card shops, magazines, etc.
Some promo cards are VERY limited and difficult to find. Sometimes, that's part of the fun of tracking them down. Sometimes, though, the cards are SO limited that there's very little hope for a collector to obtain one.
I have approximately 2 dozen 3" binders filled with nothing but promo cards. That amounts to about 10,000 individual cards.