Solid line = floor (spellings that unambiguously belong to the group). Shaded band up to the dashed edge = ceiling (the most it could reach if every ambiguous spelling counted here).
Reign has been climbing in recent years. All-time it's been given to 30,564 U.S. babies, the 386th most common name by sound today, peaking at 2,173 in 2022, with 1,837 in 2025.
By sound, Reign also includes the spellings Rayne, Rain, Raine, Reine.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).