Sat here nursing my 7 week old.
Mine are:
Grosnugs for when they're too small for Grobags so you don't have to take them out of their covers at night to feed. Then Grobags.
I have a snuzpod this time (bed side crib) which is making night feeds much easier. Got it second hand on eBay. All the fabric comes off and goes in the machine and bought a new mattress.
Baby has one bottle a day so I can get a bit of sleep and in readiness for if I ever need to be out without her- use medela calma which are active suck rather than free flow so reduce chance of bottle preference developing. They've worked really well.
Stretchy wrap sling. Baby doesn't like to be put down so this is a life saver to still be able to do things.
Nose sucker and saline spray. She had a cold at 4 weeks and these are the only things you can use before 3 months. Good to have in ready.
Sock ons or tie on socks - baby socks fall off all the time.
Zip up body suits/sleep suits are handy, but not essential.
Thin fleece snow suit that can be worn in a car seat. The puffy quilted kinds or thick lined fleece ones can't be worn in the car, so you have to take them on and off which is annoying if baby is sleeping.
They're def my most useful so far.