Nappy rash cream
something to wrap your baby in
spew rags (get twice as many as you think you will need)
a bouncer / rocker / swing to put the baby in when you need to get stuff done
a baby wrap / carrier (like a hug-a-bub)

Something I found invaluable was buying three poppers of ready-to-drink formula. I desperately wanted to bf but having an emergency supply turned out to be essential when I suddenly developed problems.

A dummy (even if you hate them, you might change your mind at 3 am one morning)

Newborns don't need much at all. Just lots of time and hugs.