Costco sized pack of towels. Not bad ass 1000 thread-count ones or something insane ones, just stuff you can use to clean up spit-up and messes. When kids vomit, it all comes out.
Hand towels and face towels really.
You’ll go thru a ton of bottle nipples depending on your kid. There are a ton of styles too.
Buy each style and go from there. Our son would gum the nipples and it would basically enlarge the opening a ton. So day 1 he wouldn’t flip out but like week 2 he’s be getting food like it was a faucet.
Watch the wipes you use and if you notice that they always have rash, try changing wipes.
Our son would get SUPER bad diaper rash (Like open sores bad) if we used huggies wipes. We switched to Costco generic brand and never had another issue.
Depending on your family, your kid may outgrow things like mad.
Try and have things a couple sized away from newborn ASAP. If your family is taller / bigger on average you may not even have them in new-born things more than like day 1 or so. Our son was like that, wife was super sad. Had a ton of things that she wanted him to wear but he was just too big for them.