Atreyu sits next to 3 phonetic neighbors — Tre, Drayco, and Arayu are the closest matches by sound. Most share Atreyu's German-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"invented name; possibly son of the fearless one"
"from the burnt clearing"
"from the angel clan"
"dark-haired"
"scholar"
"to pull, from Norman surname Tirel"
"little dark one"
"deer people (from Devon)"
"from the pool or marsh"
"ruler of the people"
"variant of Lakin: small play, sport"
"little king"
"marshy land by a lake"
"famous army, warrior people"
"high settlement or estate"
"lime tree hill"
"modern invented name"
"Yahweh saves"
"blue-purple dye, the color indigo"
"gift of God"
Similar sound: These names share phonetic patterns with Atreyu — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Fictional (Michael Ende, 1979) origins, giving them the same cultural heritage as Atreyu.
Rhythm: Atreyu is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.