Moist loo roll (Andrex washlets or similar) I still can't go anywhere without it (think that might be psychological now...) 
And a hair wrap towel. DS always woke up as I was getting out of the shower and demand feeding. A normal towel would flap in his face and without a towel if drop all over him, Its made life so much easier.
We had a cosatto bobbin bouncy chair, it was fab! It can sit up to bounce, or recline to lie flat. The DCs always slept in it during the daytime when they were little. It has a battery bit too, but I never actually got around to buying the right size batteries both dCs are too big for it now Ours broke because toddler DS tried to use it as a trampoline, I called cosatto and they sent replacement parts te next day - their customer service is fab.
Muslins. Lots and lots of muslins!
Triangular dribble bibs. Both of ours were reflux babies and these were the best at catching everything, stops the sick getting in their neck folds quite as much.
I had a moby wrap thag I couldn't live without. We live in the sticks and go on country walks a lot, couldn't have done without it.
A cot mobile that plays and spins for about 15mins. We had a fab jungle one from John Lewis by 'tiny love' it kept DS occupies long enough for me to have a shower / get dressed he loved watching the animals spin.
Cheeky Wipes! Reusable cloth wipes. Not for everyone, but so so easy to use and are so much better at cleaning up than disposable wipes.
And preferably have a minion on hand to make you drinks / bring you books / pass you things whilst you're breastfeeding. I remember being stuck under a sleeping baby for half an hour, with some god-awful TV show on and the remote control was just out of reach... :(
Good luck with everything OP. But as much or as little as you want. So long as you have plenty of vests & sleepsuits, a blanket or two and a stack of muslins everything else is extra x