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).
Brantley
Brantley is now well below its former popularity. All-time it's been given to 32,435 U.S. babies, the 778th most common name by sound today, peaking at 3,399 in 2014, with 614 in 2025.
Brantley has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).