Gay sits next to 4 phonetic neighbors — Faye, Mae, and Ray are the closest matches by sound. Most share Gay's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"joyful, merry, carefree"
"moon"
"gladness, delight"
"excellent, outstanding"
"Bright fame; from Germanic elements hrod (fame) and possibly relate..."
"from Crete, the island"
"breath, the living one"
"noble and bright"
"Dweller at the marsh"
"short form of Valerie or Valentina"
"land of the Bamar people"
"victory of the people"
"resolute protector"
"nourishing, kind"
"blind"
"sorrows, pains"
"from the island of Thera"
"of good birth, aristocratic"
Similar sound: These names share phonetic patterns with Gay — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old French (gai) origins, giving them the same cultural heritage as Gay.
Rhythm: Gay is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.