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"
"little rock, harmony"
"from the River Clyde"
"brave lion, lion-strong"
"messenger, herald"
"the bear"
"God is gracious"
"gift of God, blessed one"
"son of the lion"
"from the rye field"
"one who helps"
"lying flat (large book)"
"lover of horses"
"fair, white, bright"
"seven; divine completion"
"famous land"
"to heal"
"divinely selected (spiritual connotation)"
"growth, abundance"
"great surrounding sea"
"dove"
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.