The museum's collection includes many famous paintings.
The library's valuable holdings are on display.
コレクション is a broader term for any collection, personal or institutional, while 所蔵品 specifically refers to items held by an organization.
Compound of 所蔵 (shozō, 'possession, holding') + 品 (hin, 'article, item'). The word follows a standard Sino-Japanese pattern for items in a collection.