I would suggest t-shirts and pants instead of onsies. They have shirts by Gerber and carter that you can get at babies r us that snap on the side. It is great cuz you can lay it under baby then slip arms in, much easier then putting something over a little ones head.. If you do onsies you will still want pants as it is best not to snap close until the umbilical cord has fallen out. You will need as much air getting to the cord as possible until it falls out. Other than that...hmmm....to be honest they have all the eessentials at the hospital. A hat would be good, tho I think all hospitals give you this as well. I am very bad at planning and honestly used very few things in my bag lol. Two burp clothes are also nice for ride home. A nurse showed me to roll them up and put them on either side of their head for the ride home so as to help support the head in the car seat. Lastly...I have only had csections so far so I dont know how much bleeding there is after a vaginal but I am guessing similar. But they give awesome huge pads and throw away underwear at the hospital...thus sounds horrible but I stocked up on them and put one in my bag every time I used one lol. They are expensive to buy and so nice to not have to worry about ruining your own, or my biggest fear was that my underwear would sit right on the incision unlike these granny panties lol.
Make sure before your discharged from the hospital that u have an up to date infant car seat or they won't let u leave at least that's how it always went every time at Crouse hospital
It seems like your good to go, I can't remember what else to take for baby. I'll keep an eye on your post in case there's anything else so I can make my list, lol. ;) ... but you did mean only for baby right?