Onyx sits next to 3 phonetic neighbors — Phoenix, Lennox, and Knox are the closest matches by sound. Most share Onyx's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"claw, fingernail (Greek)"
"hillside lake, brae near the loch"
"fern plant, feathery frond"
"possessor of goodness"
"baby kangaroo (informal)"
"gifted, beautifully unique"
"pure, victorious meadow"
"reborn, born again"
"dweller near the ash trees"
"all-encompassing, entire"
"graceful ray of light"
"eternal beauty, unfading"
"queen of the gods"
"noble, eagle"
"shining upon men"
"descendant of Séaghdha"
"joy, happiness, delight"
"meadow near the water"
"pearl"
"bird"
"modern invented name blending Aaliyah and Malaysia sounds"
Similar sound: These names share phonetic patterns with Onyx — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Onyx.
Rhythm: Onyx is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.