A sidecar/co-sleeping cot and the safe guidelines for co-sleeping in case you get exhausted. You don't need to co-sleep full time if it makes you anxious but knowing how to set yourself up just in case you fall asleep could save your baby's life.
A really good computer game you can play one-handed (in a comfy chair while feeding!) or a subscription to a new streaming service with lots of things you haven't watched yet on it, or a kindle Paperwhite with loads of books you want to read. Or all three!
A supportive partner (unfortunately you can't buy this one!)
Female friends who have or are going through the baby thing as well to talk to - if you haven't signed up to antenatal classes, consider it just for this! And/or join your MN bump thread - check in Pregnancy and Birth Clubs, there is usually one on there and often they have a FB group or whatsapp group for even more chatting!
Lots of ready made food - batch cooking to reheat, nice ready meals (I like the Aldi steam fresh ones), credit/money set aside for takeaways. If you have a partner and they currently don't cook, buy them a basic cookery book now (Jamie's Ministry of Food is great) and get them practising! Also, easy, quick, calorific but non crumby snacks.
Phone numbers of the breastfeeding helplines.
Feeding pillow - useful for pregnancy sleeping as well.
A portable charger for your phone and the longest charging cable you can find (take this to hospital!!)
As you're due in summer, an insulated water bottle (Like Chilly's or unbranded equivalent) to keep water cool and at hand.
Waterproof mattress protector for your bed, and the baby's cot. Double layers of sheets on the baby's cot so if they puke in the night you can just rip the top layer off. Towels near your bed so if they puke/nappy leaks in your bed you can just cover it up and not have to change the whole bed. That's where the mattress protector needs to be good.