Kasper sits next to 4 phonetic neighbors — Casper, Jasper, and Kaspar are the closest matches by sound. Most share Kasper's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"treasurer, keeper of treasure"
"lawful, proper"
"ruler of peace"
"eagle power, eagle ruler"
"god's field, divine meadow"
"from Hadria (dark one, sea)"
"peaceful ruler"
"rowan tree"
"from the, of the family"
"divine reward"
"from the Egnatius family name"
"power of peace"
"brave in counsel"
"God is gracious"
"occupational surname for cellar manager"
"overseer, tenant farmer"
"carrier of the anointed one"
"eagle"
"invented name; possibly son of the fearless one"
Similar sound: These names share phonetic patterns with Kasper — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Persian origins, giving them the same cultural heritage as Kasper.
Rhythm: Kasper is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.