Jesper sits next to 4 phonetic neighbors — Jasper, Jesse, and Casper are the closest matches by sound. Most share Jesper's Dutch-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"treasurer, keeper of treasure"
"counsel, advice"
"Thor's stone"
"peaceful ruler"
"From; of the fen or marshland"
"wealthy, God's gift"
"elder brother, wise child"
"wealthy friend, prosperous companion"
"will-bright, famous will"
"holly tree"
"from Lucania"
"protected dwelling"
"peaceful ruler"
"frenzied, poetic inspiration"
"archer"
"mine, my own"
"valley"
Similar sound: These names share phonetic patterns with Jesper — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Persian via Old French origins, giving them the same cultural heritage as Jesper.
Rhythm: Jesper is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.