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).
Zaid has been climbing in recent years. All-time it's been given to 12,355 U.S. babies, the 798th most common name by sound today, peaking at 844 in 2025, with 844 in 2025.
By sound, Zaid also includes the spellings Zayd.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).