I will reveal them in manageable chunks, from A to Z, according to the country name that was commonly used at the time the QSL was issued.
Australia: Radio Australia
Austria: OEI (Osterreichuscher Rundfunk)
Bulgaria: Radio Sofia
China: Radio Peking
Radio Peking's QSL card initiated a flood of propaganda (Mao's "Little Red Book," a huge Mao poster, calendars, magazines, more books, etc.) that the mailman delivered to my home for years following the QSL. So much so that my father went to the local Post Office to see if he could stop it (he could not). As a result, I never QSL'd Radio Havana because they had a reputation for sending propaganda in quantities that rivaled Radio Peking.