Seeking the national costumes of the ten ASEAN countries

Your question is too broad, because there are many ethnic groups in the 10 ASEAN countries (for example, there are more than 60 ethnic groups in Laos and more than 100 ethnic groups in Indonesia), so you can only briefly talk about the main ethnic groups (the picture shows Baidu):

1, Vietnam-Aodai (female)

2. Thailand, Myanmar and Cambodia-Sarong

3, Laos-tube skirt (female), sarong (male)

4. Philippine-Balongtagalog (male), Terno (female)

5. Malaysia-Kabaya (female), Malay (male)

6. Indonesia-Bhatti shirt (male), sarong, shawl and headscarf (female)

7. Brunei-Balu+Shalong (male), long-sleeved jumpsuit without collar+headscarf (female)

8. Singapore-cheongsam (female) and Tang suit (male)