Harlan sits next to 5 phonetic neighbors — Harley, Harlow, and Harlen 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
"grey land, rocky ground"
"strong noblewoman"
"famous father"
"follower of Christ"
"weary, tender"
"crowned with laurels (via Stephanie)"
"clear, unsullied"
"from the oak, wise one"
"country; land"
"land of the Welsh people"
"a short novel, fictional narrative"
"holiest city in Islam"
"divine hospitality; gift of grace"
"fair lady, white and smooth"
"heathland, hay valley"
"gift of God"
"whole, universal"
"celestial royalty"
"modern invented blend name"
"small bouquet of flowers"
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.