Llewellyn sits next to 4 phonetic neighbors — Llewelyn, Llewyn, and Lewin are the closest matches by sound. Most share Llewellyn's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"lion-like"
"raven"
"fair, blessed"
"Shade or darkness cast by an object blocking light"
"son of Roderick"
"from the Liffey valley"
"red-haired king"
"benevolence, humaneness"
"immortal"
"hawk, falcon"
"silver, bright, shining"
"son of the wave, born of the sea"
"God has remembered"
"Maker of barrels and casks"
"wolf counsel (from Ralph)"
"from the fort (place name origin)"
"westward direction"
"claw, swift predator (via Talon)"
"rejoice; pure"
Similar sound: These names share phonetic patterns with Llewellyn — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Welsh origins, giving them the same cultural heritage as Llewellyn.
Rhythm: Llewellyn is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.