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"
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.