Vienna sits next to 4 phonetic neighbors — Viena, Vivienne, and Sienna are the closest matches by sound. Most share Vienna's German-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"white or bright settlement"
"bright, shining"
"pearl"
"bright, shining one"
"birdlike, of the birds"
"rule, sovereignty"
"little one, darling"
"happy one"
"protector of men"
"young attendant to a knight"
"free woman"
"from France, free one"
"lake + lake (Welsh llyn)"
"grace, favor"
"sea, ocean"
"father rejoices"
"jazz music + beauty"
"of the Magdalene order"
"ambergris, waxy substance"
Similar sound: These names share phonetic patterns with Vienna — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Celtic origins, giving them the same cultural heritage as Vienna.
Rhythm: Vienna is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.