Collector's items are items that are sought after by collectors due to their rarity, age, or other factors. Common collector's items include debts, curios, sets, bills, VIRTU, stamps, and rarities. Debts are sums of money owed by one party to another. Curios are objects of interest or curiosity. Sets are collections of related items. Bills are documents that represent a debt or promise to pay. VIRTU is the quality of being rare or unusual. Stamps are small pieces of paper that are used as evidence of payment. Rarities are items that are scarce or hard to find.