Here's a current offer from Agoda.
Exclusively for Mastercard Holders Receive a Further 10% off on top of incredible worldwide deals
From Terms & Conditions:
- 10% off when you save Mastercard® cards that are issued in Australia on Agoda
- Book Period: 1 July to 30 September 2019
- Stay Period: 1 July 2019 to 31 January 2020
- Destination: Worldwide
- Devices: Website landing page only - Not applicable to Agoda App
Edit: AmEx Link
One month it's MasterCard, next month it's AMEX…