Came across this topic and like to share my opinions. The first thing to note is low risk results in decent returns. If you're comfortable with slow but conservative progression, investing in etfs should suffice.

STI etf may be the first viable option as you're clear of the companies listed in the index.

Vanguard can be in your choice as it's diversified and demonstrated good spreads

S&P500 is an alternative which focuses on US companies, relatively safe over the years

I've stated the ones who proven themselves to endure the markets through statistics