Newbie working mom trying to save and maximize yield returns?

I'm 32yo wking mom and parking 70k untouched (which I understood is the cap) sitting in my ocbc 360 for rainy days/ liquidity purposes (>12mths of my income just in case). I considered myself a med risk taker and thinking to put my additional 25-30k to generate higher yields. These are my considerations and whether if etf/ssb/FD would be most viable? 1) Prepared to let this $ sit around for 10-15yrs if need be. 2) I may add funds to this instrument over time if it is still the best yield tool