Thanks, PhuketMark, for sharing the Thai ASEAN stamp (Page 10 in this thread, August 2019).
PhuketMark: The ten nations of the ASEAN Economic Community (AEC) have decided to issue common thematic stamps every two years. The first of these depicts national costumes and were issued on August 8, 2019 (ASEAN Day).
Most of the countries issued a single stamp but Myanmar released ten and Laos included a striking souvenir sheet with its single stamp (both of which seem to be the most difficult to obtain here).
Thus far, I only have the stamp from Thailand but will be obtaining several of the others as I can....
Here are all the issued stamps from the ten ASEAN (Association of Southeast Asian Nations) country members:
Myanmar is the only country issued a set of 16 stamps shows costumes of the main ethnic groups of the country:
I find the Singaporean stamp the most beautiful and attractive: