If you plan to breastfeed, you need a nursing pillow (Boppy or My Brest Friend), a breast pump (check your insurance — most cover one at no cost under the ACA), milk storage bags, and nipple cream. You may also want a breastfeeding positions guide bookmarked on your phone for those first challenging sessions.
If you are formula feeding, you need bottles (start with small sets of different brands), formula, a bottle brush, and a drying rack. Do not buy a massive supply of one formula brand — babies can be sensitive to specific formulas, and you may need to switch.
If you are combo feeding (both breast and bottle), you need supplies from both lists. Many parents start with breastfeeding and introduce bottles in the first few weeks. Having bottle supplies ready means you are not scrambling if breastfeeding is harder than expected or if you simply want the flexibility.