@ualo From my experience, every debit and credit card (Visa or Mastercard) I’ve added has worked. This includes all my debit card and credit cards from Europe, the US, and Canada.
However, it’s important to know that Curve can only charge your cards in a supported currency. Since the currencies for the UAE and Malaysia are not supported by Curve, they could only be charged in the supported currencies (e.g. EUR, GBP, HKD, etc).
Since HKD is a supported currency, you can add a card from Hong Kong and choose HKD as the currency Curve charges, avoiding any extra conversion charges. However, for cards in currencies that are not supported, it might not be worth it using it with Curve if the card has conversion charges.
With prepaid cards, Curve seems to be a little more selective. I tried adding an Irish and French prepaid card and it didn’t work. I messaged Curve about it and they said they will consider adding them. I had no issues adding my Revolut and BNext prepaid card.