Andersen sits next to 4 phonetic neighbors — Anderson, Anders, and Andrew are the closest matches by sound. Most share Andersen's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of Anders; son of the manly one"
"place of meeting"
"hollow stone, hollow hill"
"palm tree, upright"
"pastoral paradise dweller"
"sanctuary, sacred space"
"supplanter, one who grabs the heel"
"magnificent one"
"sea/pure/rejoice (Kai) + son of (-sen)"
"world ruler, ruler of the world"
"son of encouragement"
"clear, bright"
"modern American blend name, no single etymology"
"rhythmically invented name"
"great peace"
"helped by God, God has supported"
"son of Grace, gracious one"
"divine wonder"
"descent, descending"
"ruler of the estate"
"fire of God"
Similar sound: These names share phonetic patterns with Andersen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old Norse origins, giving them the same cultural heritage as Andersen.
Rhythm: Andersen is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.