I was going to do a Top 10 list in honor of Tad's half-birthday, but then I thought of too many things. Obviously your mileage may vary and all that. So, in no particular order:
1. Short-sleeved white onesies + Oxyclean.
I use the plain white onesies for layering--useful if you have a baby in the dead of winter. I don't like the one long-sleeved one he has because it just gets bunched up under his sleeper sleeves. Side note: I always size up in these. So, for example, Tad is currently wearing 9m Carter's sleepers over 12m bodysuits.
The Oxyclean is an essential partner to the white onesies, because somehow they attract poop stains like no other article of clothing. A nice long soak in an Oxyclean bath gets them good as new.
2. Zip-up cotton sleepers.
Because let's be real, you're not going to have the time or energy to dress your baby in actual clothes for the first 2 or 3 months. I know there are people out there who swear by the snap-up sleepers, but I can't stand them. They take forever to snap up and the baby wiggles and cries and then they gape awkwardly. Zippers 4 lyfe.
Also cotton, even if your baby is born in the dead of winter, because babies are in and out of their clothes all the time so you are going to keep the heat cranked up and then the baby will get all sweaty in their microfleece sleepers.
3. A medium wet bag.
These are a cloth-diapering staple (remind me to write that post sometime...) but even if you wouldn't touch a cloth diaper with a 10-foot pole, you need one of these. Preferrably two. Because at some point your baby is going to poop all over his clothes while you're out in public, and you will appreciate being able to stuff everything in the wet bag and just dump it into the washing machine when you get home. You're welcome.
4. A snot sucker.
I think these are actually called bulb aspirators or something, but my family calls them snot suckers. You can get them for free in the hospital or for about $5 off Amazon. (Which is a lot cheaper than a hospital birth, so if you were going to reconsider homebirth due to free hospital loot, don't.) I hate snot more than poop and vomit combined, but I still use this thing all the time.
5. A Boppy.
Mine has a waterproof cover and a regular fuzzy cover. I ordered a second cover just yesterday. I've only needed to change the waterproof layer once, when the baby had a major poopsplosion while nursing, but the outermost layer gets dried milk and spaghetti sauce and stuff all over it on the regular.
6. A ring sling.*
This saves my sanity on a regular basis when the baby WILL NOT SLEEP. It's also handy for grocery shopping without having to take up 90% of your available cart space with the giant car seat.
I've been trying out a woven wrap (borrowed from a friend) the past couple of weeks, and I like that too, especially for longer walks with my now-heavy baby, but the ring sling is still the workhorse of my babywearing arsenal.
7. A bed rail.*
I spent weeks stressing over the purchase of a crib my baby used maybe half a dozen times. We borrowed a bedrail from my in-laws when he was about 3 weeks old and never looked back. Cosleeping 4 lyfe. (Given how attached he is to me, it might very well be 4 lyfe, but at least we sleep. YAY SLEEP.)
8. A swing or some other* electronic baby-soothing device.
Because sometimes you get tired of wearing the baby or have to handle raw meat or something. The swing I have is a tiny portable battery-operated one and it supposedly has a weight limit of 25 pounds, but it stopped being useful for us around 4 months/14 pounds, because Tad started trying to do sit-ups while riding in it. *sigh* I still miss the days of the baby sleeping without touching me.
9. A playmat, exersaucer, or other baby-entertainment device.
For when Baby outgrows the aforementioned swing. We have both a playmat and an exersaucer. Lately I've also been sticking him in his high chair with some blocks. He gets bored easily, so sometimes I just rotate him through all three at 15-minute intervals.
10. Netflix, Amazon Prime, or some other adult-entertainment device.
Because when your baby is tiny, you are going to spend a LOT of time sitting around in bed or on the couch. We use my parents' Netflix account, but if you don't have parents with Netflix and can't afford a membership, at least do the 30-day free trial.
11. La Leche League.
Seriously, I would breastfeed all over again just to get to be friends with my awesome group of ladies. (And I don't particularly enjoy breastfeeding, so that's saying a lot.) One of my biggest breastfeeding-related regrets is that I ignored the recommendation to attend meetings while pregnant because I thought I didn't need the support. You need the support. Go to meetings.
*(Please note that some of these links are meant to give an example of a general category and are not products I have actually used.)