Nebula sits next to 5 phonetic neighbors — Nebula, Nebula, and Stella are the closest matches by sound. Most share Nebula's Latin-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"cloud, mist, fog"
"orchid flower"
"radiant one"
"Most holy"
"at a crossing, toll collector"
"celestial, divine"
"pledge, oath, solemn promise"
"star"
"lioness, brave as a lion"
"boomerang, returning stick"
"beloved"
"coral (ocean organism/color)"
"to bind, captivating"
"origin, beginning, creation"
"name of God"
"ewe of heaven"
"Derived from McKenzie; son of the fair one"
"the beautiful one"
"variant of Sheila (blind one, or heavenly)"
"divine gift, grace"
"beloved, dear"
Similar sound: These names share phonetic patterns with Nebula — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as Nebula.
Rhythm: Nebula is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.