I hate working with samples since good ones are hard to find, so I record my own or use plugins most of the time. You can try splash sound - indie voices, it’s not a sample pack but a vocal plugin which has short wo-melody maker, a mm-vocal pad and hey-shouts, it costs only $5 at the moment since it’s on sale, good for any stock music composer for that price. Also if you have more to spend, There’s eastwest hollywood backup singers plugin with a wordbuilder that would help you for years. Then for more lyrical vocals ethera gold intimate vocals which is on intro discount around $30 since it’s brand new
Edit: Oh yeah there’s also Realivox Ladies which is also great for stock music but even though it’s on sale at the moment, it’s still $200. But you should at least check it out for the future.