We forgot a comb & hairbrush. Our DD was born with a full head of hair, was a huge surprise.
One thing I didn't get around to before the birth was making a no-sew stretchy wrap (DIY hug a bub). I bought the fabric but didn't cut to size. I did it quite hastily after bub was born and then had to watch you tube vids to learn how to tie it. Really wish I'd been more organised so it was ready from day 1.