Boyd sits next to 4 phonetic neighbors — Lloyd, Floyd, and Doyle are the closest matches by sound. Most share Boyd's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"blond, yellow-haired"
"broad valley"
"one strength, unique strength"
"round hill, hillock"
"rain, precipitation"
"atmospheric mist, haze"
"page boy, herald"
"curly-haired"
"sun, shepherd"
"son of the spear-ruler (Gerald = Geirald)"
"son of the famous ruler"
"slender one, the thin one"
"the winter season, wet season"
"deer meadow"
"home ruler, lord of the estate"
"from Rome (Rum/Anatolia)"
"muddy farm or settlement"
"leopard, swift and agile"
"victory; honor"
Similar sound: These names share phonetic patterns with Boyd — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Scottish Gaelic buidhe origins, giving them the same cultural heritage as Boyd.
Rhythm: Boyd is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.