Sonder sits next to 4 phonetic neighbors — Sander, Sondar, and Thunder are the closest matches by sound. Most share Sonder's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"the realization that every stranger has a full and vivid life"
"passionate devotion, fervor"
"supplanter"
"one who lives by hawthorn bushes"
"divine mother goddess (Irish)"
"new day, new light (interpreted)"
"pure strength"
"modern invented name"
"peace, repose"
"one who rules"
"Greece, Ionia (land of Greeks)"
"homestead on the rock"
"born of laughter, joy"
"rejoice, be happy"
"short form of Bradley or Bradford"
"heron bird, large wading bird"
"little battle, warrior spirit"
"God will add, increase"
"worthy, of value"
"new house, new home"
Similar sound: These names share phonetic patterns with Sonder — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Neologism from German sonder + French sonder origins, giving them the same cultural heritage as Sonder.
Rhythm: Sonder is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.