cards vs trading card

cards

noun
  • card games 

trading card

noun
  • A collectible card, sometimes sticker, usually made out of paperboard or thick paper, which usually contains an image of a certain person, place or thing (fictional or real) and a short description of the picture, along with other text (attacks, statistics, or trivia). There is a wide variation of different types of cards, like sports, cars, natural history, film characters or other information of interest to purchasers. Sometimes is included with tobacco, food or confectionery products. 

How often have the words cards and trading card occurred in a corpus of books? (source: Google Ngram Viewer )