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"
"muddy place, ditch"
"rib, side"
"bold place, wild settlement"
"from Mauritania"
"young warrior, free man"
"from the Roman family Terentius"
"battle, warrior"
"at the cattle sheds, one from the byres"
"village of the cross, farm by the cross"
"admirable, worthy"
"sprout, bud"
"brave in battle"
"narrow, a strait"
"son of the south"
"tournament fighter"
"bright, full of sunshine"
"shining with fame"
"yellow-haired, blonde"
"God is gracious"
"he who causes distress"
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.