On Xianyu (Alibaba's second-hand trading platform), you can choose rare goods based on market demand and uniqueness.

Here are some suggestions:

1. Antique collections: such as ancient coins, porcelain, jade, calligraphy and painting, etc. These items have historical and cultural value and are attractive rare goods for people who like to collect.

2. Limited edition goods: For example, a certain brand's limited edition figures, sneakers, clothing, etc. These items have high collection value because of limited release or unique design.

3. Rare items: such as customized goods, handicrafts, vintage furniture, etc. These items are unique and personalized and easy to attract buyers.

4. Software, games and electronic products: such as early game cards, software and collector's edition electronic products, these items are scarce and can meet the needs of specific enthusiasts.

5. Collectibles and souvenirs: such as commemorative coins, commemorative stamps, historical relics, etc., these items have unique commemorative value and historical significance.

6. Artworks and collectibles: such as stamps, currency, famous paintings, etc., these items have artistic value and collection value.

When choosing rare sources, please ensure the authenticity and safety of the source, and follow the platform regulations and laws and regulations during the transaction. At the same time, be careful not to violate the platform policies and relevant laws and regulations to ensure the legality of the transaction.