Kolsen sits next to 3 phonetic neighbors — Colson, Kolton, and Carlson are the closest matches by sound. Most share Kolsen's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of Nicholas, victory of the people"
"stammering, lisping"
"flowing down (from Jordan)"
"to conquer, to win"
"messenger of God"
"of Mars, warlike"
"from Percy (Norman place name)"
"land of the Bronck family"
"dark warrior"
"divine presence"
"Kryptonian birth name of Superman"
"overseer, superintendent"
"from Saint Denis"
"son of Carr, marshy land"
"God is gracious (if related to John)"
"firm, constant"
"bold, daring (thunder-bold)"
"thankful, grateful"
"counsel, power"
"little ancient one"
"belonging to God"
Similar sound: These names share phonetic patterns with Kolsen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Scandinavian/Greek origins, giving them the same cultural heritage as Kolsen.
Rhythm: Kolsen is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.