Alwyn sits next to 3 phonetic neighbors — Alvin, Elwyn, and Edwin are the closest matches by sound. Most share Alwyn's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"noble friend"
"to dazzle, stun with brightness"
"gentle, lenient"
"of the forest, woodland dweller"
"powerful person, dynamic one"
"of the shade, of the shelter"
"gray color"
"descendant of Bibb, a pet form of Isabel"
"bright, shining warrior"
"spear bearer, warrior"
"bright; swift"
"thorn, prickly plant"
"Modern invented name; energetic and bold spirit"
"Of the forest; made of wood"
Similar sound: These names share phonetic patterns with Alwyn — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English aethel + wine origins, giving them the same cultural heritage as Alwyn.
Rhythm: Alwyn is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.