Larsen sits next to 4 phonetic neighbors — Larson, Lawson, and Lars are the closest matches by sound. Most share Larsen's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of Lars"
"benevolence, humaneness"
"middleman, arbitrator"
"son of Stephen, one who wears the crown"
"serious, earnest"
"variant of Elias: my God is Yahweh"
"modern coinage, possibly 'thankful lion'"
"narrow (place name origin)"
"something deserved, virtue"
"gathering place, pool"
"Athenian, of Attic culture"
"strong-willed warrior"
"son of Braxton"
"modern invented name, combination of Tae and -vion"
"lord, master (Ky- root from Greek Kyrios)"
"bright, splendid"
"tile maker, tiler"
"summoner, one who calls forth"
"God has remembered"
"fictional Fire Lord, invented name"
"cold well; from the cold water source"
Similar sound: These names share phonetic patterns with Larsen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Scandinavian patronymic origins, giving them the same cultural heritage as Larsen.
Rhythm: Larsen is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.