Herschel sits next to 4 phonetic neighbors — Hersh, Hershel, and Hershl are the closest matches by sound. Most share Herschel's Germanic cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"deer, stag"
"friendly people"
"elm grove"
"oak tree, strength"
"modern invented name with Ry- prefix"
"luxury, abundance"
"strength, permanence"
"angel, divine messenger"
"initials, often James David or John David"
"one who finds the way, wayfinder"
"beautiful and good"
"servant of Saint John"
"invented modern name, possibly blade-valley"
"Lord have mercy"
"helped by God, whom God helps"
"sand hill, sandy mound"
"from the craggy hills, little hill"
"to increase, to grow"
"one who inscribes"
Similar sound: These names share phonetic patterns with Herschel — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Yiddish/Germanic origins, giving them the same cultural heritage as Herschel.
Rhythm: Herschel is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.