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"
"counsel wolf"
"of the mountain, from the mountain"
"drawn out of the water"
"from the Brazos River, Texas"
"the sun, solar light"
"from Hadria (a Roman city)"
"great happiness, delight"
"bear man, noble bear"
"legend, heroic story"
"modern invented combination of grey + len"
"life, living existence"
"in the shadow of God"
"independent"
"my, mine (Tagalog possessive)"
"modern invented name"
"strong and enduring as oak wood"
"rising in the east; the hunter"
"thanksgiving, praise to God"
"victory of the people (via Nico)"
"from the settlement near St. Botolph"
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.