You got Citi Plat and Citi CB and SCB Biz Plat (Cash Back).

For petrol, I guess for your case UOB One CArd and OCBC TMC no diff since you already getting 5% cash back.

For Groceries, your Citi CB also gives you 2% and your Citi Plat 5X points at many Departmental and Hypermarkets.

Once again, click here to my article on UOB One Card.I have done a sample calculation on how much one can earn from various cash back cards including Citi CB. Go do one yourself and determine if OCBC TMC and UOB One Card can earn you more than Citi CB and Citi Plat.

Having said above, I would go with OCBC TMC or Maybankard 2 Cards since your spending is less than RM1K in general and cancel the 3 cards you have and get back RM150 from GST, hahaha. But Citi recently got many places giving discount and SCB do reward pretty good gift to their card holders ( not sure if that is applicable to Biz Card). You apply SCB Plat just to get the cash offer