Cygnus sits next to 4 phonetic neighbors — Sygnus, Cyrus, and Silas are the closest matches by sound. Most share Cygnus's Latin-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"swan"
"Bright light, torch, shining one"
"star"
"brilliant helper"
"gentle, humble"
"automotive brand name"
"praised, praiseworthy"
"God is gracious"
"prosperous, equal in rank"
Similar sound: These names share phonetic patterns with Cygnus — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as Cygnus.
Rhythm: Cygnus is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.