Lots of drinks and snacks! I didn't have much appetite during labour and was still puking due to hyperemesis, so DP unbeknownst to me was eating them. When I got onto the ward I felt amazing as the sickness had finally lifted but I was starving hungry for the first time in months and all that was left was a pack of jelly tots and I had packed an ample supply of cereal bars and other sugary food for energy which were all gone . Pack more than you think you will need, or a separate bag of things for your DP/H so he doesn't pilfer yours. And none of the midwives had told me there was a room off the ward that was open 24/7 with tea making facilities and fruit and toast, so get your partner to ask where it is for you and maybe write it down, I was so spaced out on gas and air I couldn't really think straight for the first few hours.
Don't bother packing magazines or other entertainment, they take up valuable space and as I did most of my labour at home didn't need them once we were in hospital as I was ready to push and after baby was born I just stayed up all night staring at her in total awe of how beautiful and amazing she was.
Lanisoh is essential if you want to breastfeed. Lots of Muslins are good too DD was very pukey at first and I got through at least 5 in the one night I was in for. Button down nightie is good if breastfeeding too. Nursing bras too.
I got my DM to deliver my nice goosedown pillows from home to me too, in bright covers that wouldn't be mixed up with the hospital ones, and although I didn't sleep I was much more comfortable propped up on them to feed than I would have been on the hard flat hospital ones.
Maternity pads in copious amounts and big comfy 'granny' knickers, I got some a few sizes up and they were a godsend.
A lot of vests and sleepsuits as if you have a baby that vomits you will get through a lot in one night, plus if you don't put a nappy on quite right in an exhausted state there will be leaks!
A full pack of nappies and cotton wool pads, nappies with a wetness indicator strip are good as you don't want newborn skin sitting in urine for any length of time and wipes can irritate their delicate skin.
Keep your going home clothes in the car so they are not taking up space and making other stuff harder to find while you're on the ward.