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"
"victors garland"
"fifth-born child"
"throne"
"sacred, holy"
"noise, tumult"
"elf friend, noble friend"
"remnants of the lake"
"descendant of Cinneide"
"mountain"
"brave spear, strong with a spear"
"eagle"
"God has been gracious"
"lord, father, sovereign"
"scarce, seldom"
"strong as an oak"
"lion"
"new house, bright"
"God is salvation"
"hawk-like"
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.