Hardin sits next to 4 phonetic neighbors — Harlan, Hayden, and Harden are the closest matches by sound. Most share Hardin's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"valley of the hares"
"son of the prosperous protector"
"sacred, belonging to the divine"
"greatest stream (via Maxwell)"
"fair-skinned, son of the fair one"
"may God protect"
"modern invented variant of Zayd"
"to heal (if derived from Jason)"
"Yahweh has given"
"he who resembles God (rhetorical)"
"peaceful ruler"
"pledged, devoted"
"young wolf"
"set apart, destined"
"peace power"
"from the pool or marsh"
"from the River Irvine"
"impulsive, little king"
"firm, unwavering"
"occupational surname for cellar manager"
Similar sound: These names share phonetic patterns with Hardin — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English origins, giving them the same cultural heritage as Hardin.
Rhythm: Hardin is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.