How to read the band →
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).
Rhett
Rhett has been climbing in recent years. All-time it's been given to 36,920 U.S. babies, the 354th most common name by sound today, peaking at 2,554 in 2021, with 1,955 in 2025.
Rhett has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).