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"
"lion-like, descendant of lions"
"love, passion"
"son of Rawlin"
"ruling"
"modern American invented name"
"blessed"
"son of grace, son of good fortune"
"initials standing independently"
"black, swarthy"
"Yahweh is gracious"
"celestial, relating to heaven"
"craftsman, smith"
"born of the ocean wave"
"cushion (alternative Irish etymology)"
"hollow, vain (from Latin Cassius)"
"from the ledge farm, shelf settlement"
"gift from God"
"brewer, one who brews"
"son of Tray"
"son of Jack"
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.