Kelvin sits next to 3 phonetic neighbors — Kevin, Melvin, and Gavin are the closest matches by sound. Most share Kelvin's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"from the River Kelvin, narrow river"
"raven-like, dark as a raven"
"goodness of Yahweh"
"chief, lord"
"salmon"
"yellow, golden"
"protector of mankind"
"sea"
"wealthy, kingly, upholder of good"
"from the mouth of the Roe river"
"of noble renown"
"heart brave"
"little ancient one"
"west wind"
"rule of the spear, spear ruler"
"genuine, real, authentic"
"slender, bright-headed"
"ruler of all, universal ruler"
"son of the brown-haired one"
"prince, chieftain"
"resolute protector"
Similar sound: These names share phonetic patterns with Kelvin — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Brythonic Celtic origins, giving them the same cultural heritage as Kelvin.
Rhythm: Kelvin is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.