THERE ARE ALMOST AS MANY COLLECTIONS AS THERE ARE COLLECTORS AS YOU CAN COLLECT STAMPS, MINT OR USED IN SINGLES, PAIRS BLOCKS, BLOCKS OF FOUR, SHEETS ETC. YOU CAN COLLECT FIRST DAY COVERS, ENVELOPES OF INTEREST, TAX STAMPS, REVENUE STAMPS, POSTAL HISTORY AND THE LIST COULD GO ON AND ON. SOMETIMES WHEN YOU COLLECT FOR EXAMPLE CANADIAN SINGLE STAMPS USED YOU MAY ALL OF A SUDDEN GET THE URGE TO COLLECT CANADA'S EARLY QUEEN ISSUES. REALLY..... THANS THE FUN OF STAMPS