Some other merchant that is using Grabpay non food --- CZipLee (stationery shop in bangsar) it is slightly upscale in price though,

Starbucks is by Berjaya group, they are partnering with Alibaba, and razer which is why alipay is available in most of their subsidiaries like SB, 7-11 I don't forsee sb adopting other payment system in the near future. Coffee bean accepts grab pay.

Citibank cash back card also gives 10% cashback for grab, I tried topping up grabpay, got 10% back. but there is a minimum spend with citi cards.