Helen sits next to 3 phonetic neighbors — Ellen, Hellen, and Alan are the closest matches by sound. Most share Helen's Greek-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"Bright light, torch, shining one"
"swan"
"dweller at the wood"
"automotive brand name"
"valley dweller"
"Trojan hero, ancestor of Rome"
"Valley of the linden trees"
Similar sound: These names share phonetic patterns with Helen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Helen.
Rhythm: Helen is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.