Congratulations on your pregnancy!
For me, these were things I was very grateful we had:
Muslins - millions of them and we always ran out lol
Dummies
Bottles and formula (as much as I wanted to BF we just couldn't get the baby to latch on so it was a good job we had formula in "just in case" - you could buy an express pump. I did that for 3 months to express breast feed
Changing bag - honestly, any old bag doesn't do. Most changing bags have sections for bottles, have a changing mat included, clip for your keys, etc. Having a decent changing bag was a game changer from the plain bag I thought would be fine to start with
Sleep suits & baby gros/vests
Blanket or play mat for them to lie on
Cot mobile
Make sure you have a decent changing station set up - you need to be able to reach everything one handed whilst stopping your baby from falling off!
Don't underestimate how many nappies you might need - subscribe & save on Amazon is a good way to buy them cheaper
Have a bottle of Calpol available in the house ready for first lit of immunisations.
Nappy sacks & wipes
Decent chair for night feeds - sitting up in bed can be really painful on your back, I had a wonderful rocking chair. I won't let my husband get rid of it 20 years on because I have so many fond memories in that chair. One with pockets on the side to stash snacks for you when you're starving or just trying to stay awake lol.
Most un-useful thing we had (was a gift) - nappy bin. It stank!