How many kinds of stamps are there?

Let me talk about China.

By category:

"Ji" prefix stamps, "Special" prefix stamps, "Wen" prefix stamps, numbered stamps, year stamps (that is, special stamps for Kyrgyzstan since 1992), "J" prefix stamps, "T" prefix stamps, promissory notes, ordinary stamps, personalized special stamps, special stamps for the New Year, stamps with words and values, and bonds.

According to the external structure:

Toothed and toothless.

According to stamp structure:

Stamps, promissory notes (many stamps with teeth on three sides must be torn off from promissory notes), sheetlets, souvenir sheets, sheetlets, brochures and so on.

Depending on the material (quality) or printing method:

Paper, silk and paper are bronzed (also called gold foil stamps).

By sales channel:

Tickets issued normally, especially matching sales, lottery sales, plus an unreleased stamp sales.

By way of sales:

Reservation, retail.

By means of acquisition (channel):

Reservation, retail, exchange, online shopping, gift, delivery (free).