I was wondering, besides Bangkok Bank's Be1st and Kasikorn Bank's Web Card, are there any other Thai bank's ATM cards (not credit cards) that can be used for online purchases?

none ... try them all before a few months ...

international usage no problem ... but internet use is just impossible

Thai Debit cards do not work online.

Naka.

Thai Debit cards do not work online.

Definitely not true.

My Bkk Bank be1st card works with the majority of the online payment gateways!

It works with paypal, I have bought books on Amazon and paid for electronic gadgets at a Hong Kong based on line store.

It's possible to get your Be 1st card enrolled in the verified by Visa program, increasing the security when on-line shopping.

A few gateways don't accept the Thai cards because of the choices in expiry date don't go 10 years in the future, but these gateways are getting fewer and fewer!

1. What is Be Secure®?

Be Secure is a new service from Bangkok Bank that uses Verified by Visa to provide increased security when using Bangkok Bank credit cards and Be1st cards to make purchases via the Internet.

From their website here