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"
"mountain goat, ibex"
"gift from God (popular interpretation)"
"noble kind"
"associated with harbor or gate (popular folk etymology from Latin '..."
"noblewoman, lady"
"helpful one, descendant of the helpful one"
"Strong lord, mighty ruler"
"heavenly sea"
"gift of Yahweh"
"slender, beautiful"
"you will always be loved"
"creative variant of Harmony or Imani"
"Pearl (via Margarita, the Latin equivalent of Daisy)"
"possessing goodness, upholder of good"
"princess, noblewoman"
"heavenly chief, ruler of the skies"
"high, elevated"
"high settlement, home farm"
"noble strength"
"Derived from McKenzie; son of the fair one"
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.