Decided to keep:

Day-to-day use:
1. Maybank/Amex Gold for the 5x MR on groceries/petrol/telco/bookstores
2. CIMB Enrich Plat for Enrich Miles

High credit limit for emergencies/overseas travel (occasional use locally when there's good promotions):
3. Citi Plat
4. StanChart Plat - can get discounts in HK/SG where I go frequently for biz

Cancelling:
1 & 2. UOB Plats (2x) - poor rewards program
3. Citi Shell Gold - don't need a 2nd Citi card, using the Maybank Amex Gold instead
4. CIMB DA - don't use it anymore anyway.

Basically keeping 2 local cards for general use here, and 2 high-limit foreign bank cards for emergencies and overseas travel.