New mum here. Lots of good recommendations, although I'm from northern Australia so the clothing I got is quite different. Babies here just need short-sleeve onesies and a light swaddle.
I recommend:
A good thermos, because you won't be able to finish your morning coffee/tea in one sitting for a while and no one likes microwaved tea.
A good water bottle. You need to keep hydrated if breastfeeding, and if getting up frequently at night.
A pack or two of terry towel cloth nappies. I don't actually use these as nappies, they are so versatile and I currently use them as burp cloths, change mat, play mat during nappy free time, cleaning cloths, face wipes... And you will use them for years to come.
Meals - over the next few weeks, cook double what you would usually cook, and freeze half to be reheated later. Post-partum you will thank you. Also prep some easy freezer friendly meals that only require defrosting and dumping in the pot eg chicken soups, curries, etc.
Groceries: before your due date, stock up on non-perishables you might run out of eg long life milk, cereal, cans of soup, pasta etc... Also buy some easy to cook food like frozen pizzas, noodles, sandwich meat and bread, etc.
If you have a vaginal birth, things will hurt down there. Get some condoms and fill them with water, then freeze them laying kind of glad. If you have a vaginal birth, you can put these icy condoms between your pad and underwear, and they are amazing for the pain down there.
Speaking of pain.. Peeing and pooing post-partum can be quite painful if you have a vaginal birth. Stock up on some gentle osmotic laxatives and start taking 1 a day from the day you give birth. It will keep things softer and make pooing a lot more comfortable until things don't hurt anymore.
Also get some urine alkilisers and take 1-2 a day along with drinking lots of water (they're what you use when you have a UTI, get the ones containing Bi-Carb Soda). This will reduce the acid level in your pee, and help it not to sting any tears or stitches. I only used these for a week post-partum, but they really helped.