Why can't I find a product review for Interactive Broker and TD Ameritrade? Thought they are quite popular for Singaporeans who are investing in US stocks.?

Yes IB is definitely one of the cheapest out there, the only downside is that there is a monthly fee of US$10 if the account value falls below US$100k.

At present, IBKR Lite account does not impose the above - but sadly, it is only available to US citizens at the moment. Or any community members here happen to know of a method to work around this?

Yup it's because they don't have an office here and they also are not a registered broker in MAS if I'm not wrong.

But it's a good point! We'll take note of it in case we add it here: seedly.sg/reviews/online-brokerages