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"
"fisherman"
"dweller by the holly"
"God is gracious"
"stellar explosion, burst of light"
"son of the south"
"one who makes wooden tubs and casks"
"strong, virtuous, honorable"
"shepherd, one who tends sheep"
"from Mauritania"
"from the marshy plain"
"dark settlement"
"to rejoice, joyful"
"free man"
"defender of men"
"faithful, loyal, trustworthy"
"noble elder"
"great forest, eagle valley"
"the island, island dweller"
"olive tree"
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.