Zeppelin sits next to 3 phonetic neighbors — Zelda, Seraphina, and Zara are the closest matches by sound. Most share Zeppelin's German-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"place name: Zeppelinheim, Germany"
"harmony"
"beloved, wished-for child"
"of Mars, warlike"
"living, alive"
"radiant angel"
"one who works with stone"
"pipe, conduit"
"God is my father"
"industrious, striving"
"sky-colored, blue"
"sublime, lofty"
"strength of God"
"gift of God"
"pure"
"lake (via Welsh llyn)"
"strong, vigorous"
"night, dark beauty (if from Leila)"
"descendant of Niall"
"life of Zeus; gift of the gods"
Similar sound: These names share phonetic patterns with Zeppelin — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Germanic origins, giving them the same cultural heritage as Zeppelin.
Rhythm: Zeppelin is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.