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"
"little king"
"free man"
"craftsman of fermented beverages"
"he who causes distress"
"ewe herder"
"rock, stone"
"from the isle"
"resolute protector, strong-willed warrior"
"great one"
"power, strength, ruler"
"awareness, understanding, learning"
"ruler of the sea"
"pilgrim, palm branch bearer"
"crooked mouth, wry-mouthed"
"yellow-haired, blonde"
"will helmet, strong protector"
"God supports, Yahweh supports"
"the fox, cunning animal"
"dove"
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.