Bro, I got no ideas on SG credit cards. The only foreign credit card I have is Citibank Australia Platinum Rewards Visa where it is FREE FOR LIFE as long as I maintain my CitiGold status. I tell you, Malaysia is the best where many banks offer FREE FOR LIFE credit cards but not the case in Australia.
Anyway, no matter where one resides, the best credit card in the world is still
Maybank 2 Cards Premier. Annual income requirement less than USD60K/year and it earns you 1 Airmile (Enrich of KrisFlyer) with less than USD0.26 spending anywhere on earth (VI outside Malaysia and AR withing Malaysia)

And one gets to enter worldwide airport lounges 5X FREE per year too

If you are working in SG and spend you money there, you get 1 KrisFlyer Miles with every SGD0.335spent (or close to 3 KrisFlyer Miles with SGD1 spent)!!!! I don't think any SG credit cards can beat this. UOB PRVI AMEX or MC only offer 1.6 AirMiles for every SDG1 spent in SG.
Having said the above, we need less Enrich Miles compared to Kris Flyer Miles to fly Business Class to say to London. EM only need 55K (KL/LHR) whereas KrisFlyer 80K (SIN/LHR). Both did not consider redeeming online where you get 15%
Bro Gen-X , Actually not only Enrich and Krisflyer, we can redeem AsiaMiles too.