Elwin sits next to 5 phonetic neighbors — Alvin, Edwin, and Elwyn are the closest matches by sound. Most share Elwin's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"elf friend, friend of the elves"
"the Lord is salvation"
"fragrant ointment"
"pledge, oath, measure"
"from the ancient city of Tyre"
"large gun, powerful force"
"strong-willed warrior"
"God has remembered"
"defender of men"
"guardian dragon of the golden apples"
"to shine, tremble with light"
"from Dyce, Aberdeenshire"
"dear, beloved"
"beloved of God (if Dai- is from Welsh David)"
"from the Liffey valley"
"handsome, distinguished"
Similar sound: These names share phonetic patterns with Elwin — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English origins, giving them the same cultural heritage as Elwin.
Rhythm: Elwin is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.