The diaper most US hospitals send you home in, and honestly the one that just works for most newborns without any drama.
If you have no idea where to start, start here. Swaddlers are blanket-soft, have a genuinely useful color-changing wetness indicator, and a contoured umbilical-cord notch in the newborn sizes that new parents love. They fit the widest range of baby shapes, which is why they're the default recommendation. Skip them only if your baby has a specific sensitivity to the fragrance or lotion, or if you're committed to a plant-based/eco option, in which case look at Coterie or Honest.