Onix sits next to 4 phonetic neighbors — Onyx, Phoenix, and Felix are the closest matches by sound. Most share Onix's Spanish-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"black banded gemstone"
"one who wields prosperity"
"heel, ankle"
"initials standing independently"
"the one who flew"
"grandchild, descendant"
"hospitality toward strangers"
"dear, beloved"
"one who works with stored grain"
"day"
"flowing river"
"Ella's town or estate"
"forest meadow"
"broad valley, wide meadow"
"man of prayer, full of goodness"
"treetop, eloquent speaker"
"divine judge"
"ruling"
"spear warrior"
"open grassy plain"
"short land, curtailed land"
Similar sound: These names share phonetic patterns with Onix — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Onix.
Rhythm: Onix is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.