A grading designation indicating that only one copy of a specific card or collectible exists at a given grade across the population reports of major grading services (e.g., PSA, BGS, CGC, SGC).

Pop 1 cards command outsized premiums because they are demonstrably the finest known surviving example. Even a Pop 1 card of a relatively common subject can sell for multiples of next-grade-down examples. The designation can change as more cards are submitted.