I’d say my best buys were:
Fisher price newborn to toddler rocker - still use it now and DS is almost 17 months - is ideal for putting him in it if I want a shower. Handy for having an option to put baby down quickly and safely too.
Karibu baby folding bath - again still in use and expect it will be a good while yet. Saves filling the whole bath everytime. Can start out using kitchen sink though.
Somewhere safe for baby to sleep downstairs that you don’t have to keep lugging around. I was gifted a family crib that did the job and kept the Moses basket upstairs.
Tenvisty webcam we use as a baby monitor, cost way less than anything billed as a baby monitor. Still in use although you won’t need this straight away.
Beanbag filled breastfeeding pillow - much preferred this to my other solid one as you can manoeuvre it better into a comfortable position.
Chilly bottle for water - breastfeeding is thirsty work and now I take it out with us to fill his cup. Likewise decent travel cup (put it in your hospital bag as the tea cups in the day room of our hospital were thimble sized - I was in a while!)
Extra large muslin cloths - have a look for Aden and anais ones, they’re often on sale in TKMaxx. Lovely and soft and can double up for swaddling, breastfeeding cover etc.
Calypso double breast pump - found out about it via Mumsnet reviews it has been worth the money for me but I did have to pump continuously from birth while we waited for DS to have a tongue tie cut. I use it more sporadically now but it’s worked out great. Stock up on milk bags too for the freezer if you intend to breastfeed.
Didn’t bother with grow eggs but I do have a couple of Ikea nightlights that have been really handy.
I also found it useful to have a number of changing mats, one upstairs, one down, one ready to go out in the nappy bag. Bonus if they are washable as oppose to just wipeable in my opinion (I like our cheeky wipes one best for this reason).
Cheeky wipes - Expensive initially but a real worthwhile investment over disposable wipes.
Morcck blanket for the car seat.