Eirian sits next to 5 phonetic neighbors — Arian, Kieran, and Orion are the closest matches by sound. Most share Eirian's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"silver, bright, shining"
"bold king, royal ruler"
"fire, flame (poetic interpretation)"
"Rowan tree"
"keeper of the keys"
"helmet of will, resolute protector"
"A dark image or form following a person or object"
"red-haired king"
"little poet"
"variant of John"
"archer, warrior of the yew"
"claw, swift predator (via Talon)"
"chief, ruler"
"son of Rawlin, son of Ralph"
"God has remembered"
"land of the Scots"
Similar sound: These names share phonetic patterns with Eirian — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Welsh arian (silver) origins, giving them the same cultural heritage as Eirian.
Rhythm: Eirian is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.