In 2005, the USPS approved vendors to sell customized stamps. People could register with the vendors, upload their own photos or designs, and print customized postage. Alas, don’t get your hopes up, Steve Mitchell (probably don’t bother Googling him — or do just for fun to see what you come up with — he’s a friend who has mentioned a couple of times that COVID cards would make great stamps), the USPS has ended this program.
COVID Card #80 recognizes the short-lived (15 years, I think) custom stamp program.