Minting/Production Error (3)
Philately - Air Mail (45)
Philately - Besieged locale (1)
Philately - Censored Mail (16)
Philately - Earliest/Latest, First/Last & Proving dates or places (13)
Philately - Military Post Offices or Military Administration (7)
Philately - Multiple Postal Authority/Period mail (2)
Philately - Postal Stationary (1)
Philately - Printed Matter mail (4)
Philately - Significant Addresses/Persons (4)
Philately - significant cachets & postal markings (14)
Philately - Significant franks on covers (53)
Philately - Significant Rates/Periods (25)
Philately - Significant Route (3)
Philately - Small Locales (11)
Philately - Stampless Mail (1)
Philately - Surface Mail (contemporary) (5)
Philately - Suspended Service mail (3)
Philately - Taxed Mail (4)
Philately - uncatalogued/undocumented varieties (4)
Philately - Unusual Origin, Destination or Postal Link (8)
Philately - unusual postal procedures/fines/taxes (6)
Unique/Discovery Piece (2)