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).
Alyssa has fallen well below its former popularity. All-time it's been given to 395,244 U.S. babies, the 590th most common name by sound today, peaking at 16,425 in 1999, with 927 in 2025.
By sound, Alyssa also includes the spellings Alissa, Elissa, Elyssa, Alysa, Allyssa, Allysa.