Earliest/Latest, First/Last & Proving dates or places (9)
Object Related Specifically to a Personality or Key Event (8)
Production error (non-stamp) (1)
Significant Addresses / Persons (4)
Significant dates (15)
Small locales (2)
Uncatalogued / Undocumented varieties (2)
Unique / Discovery items (5)
Philately - Censored Mail (1)
Unusual Origin, Destination or Postal Link (12)
Unusual postal procedures, fines or taxes (4)
Philately - Displaced Persons/Internee/POW Camp mail (1)
Philately - significant cachets & postal markings (1)
Philately - Small Locales (1)
Philately - Stampless Mail (1)
Philately - Unusual Origin, Destination or Postal Link (1)