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).
Felicity
Felicity climbed for decades and has been a steadily popular name ever since. All-time it's been given to 18,565 U.S. babies, the 883rd most common name by sound today, peaking at 938 in 2017, with 653 in 2025.
Felicity has no common alternate spellings by sound.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).