Harlan sits next to 4 phonetic neighbors — Harlen, Harley, and Carlan are the closest matches by sound. Most share Harlan's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"rocky land, stony ground"
"long narrow hill"
"record keeper"
"made by God"
"Yahweh is merciful"
"modern American creation"
"brook, small stream"
"handsome, cheerful"
"asked for, prayed for"
"Paega's settlement"
"bridge worker or keeper"
"brave warrior (later folk etymology)"
"God's helper (ezer + El)"
"king"
"crooked valley"
"carried by God"
"estate of the fifth son"
"large gun, artillery piece"
"elevated one"
"beautiful friend, fair friend"
Similar sound: These names share phonetic patterns with Harlan — 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 Harlan.
Rhythm: Harlan is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.