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"
"supplanter's son"
"gift of God"
"wise counselor"
"one who serves"
"settlement of the prince"
"farm settlement of Dudda"
"one who brings news"
"the cleansing one"
"red (hair color)"
"from Lucania"
"son of Ridge"
"thorny shrub, prickly plant"
"spear, lance"
"my God is salvation"
"bold warrior"
"people's power"
"renowned warrior"
"Yahweh remembers"
"famous spear"
"delight, luxury"
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.