OP, have you considered actually speaking to the new parents and asking whether they would like you to knit more things for them, as you love knitting and have lots of spare yarn?
I can just about keep up with my own children's likes and dislikes, but my sister has five adult children, and when their babies came along I asked them if they wanted me to knit for them and if so, what did they want. I linked them to Ravelry and said they could choose a pattern, or they could just ask for a 'thing' (eg a blanket) and leave the choice to me. One said that she'd rather I didn't spend time knitting, as she would worry that she'd spoil it in the washing machine, and the others all either chose a pattern or made a suggestion for me to choose.
Neither of my children want knitted jumpers, and although I would happily churn out aran garments for them, I buy them sweatshirts instead.
I don't think that many people now knit out of necessity or to save the new parents money, as happened in the past. We do it because we enjoy it - you said yourself that you love knitting - so it's not really about the recipient any more. Times have changed.
This is a bit of a tangent, but there are forums on Ravelry where people discuss knitting, and there are lots of posts on there from people complaining that they spend ages making a beautiful orange poncho, or purple fair isle flared trousers (I exaggerate for effect, but only slightly ?) and are deeply offended that they have never seen the recipient wearing them.
My son sent me this card for my birthday one year, and I think it says it all . . .