Jailen sits next to 4 phonetic neighbors — Jaylen, Jalen, and Jaylin are the closest matches by sound. Most share Jailen's American (folk etymology)-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"blue crested bird"
"surname of uncertain origin"
"scorching, glowing"
"He shines"
"army, nobleman"
"he who supplants, holds by the heel"
"unique, one of a kind (modern interpretation)"
"hare land, land of hares"
"limitless, beyond measure"
"friend of horses"
"standalone initials name"
"fair, bright one"
"ordained minister's helper"
"stone, solid mass"
"nickname form of Roger"
"elder, old man"
"farm on stony ground"
"God is gracious (via Sean)"
"son of Jan"
"modern American invented name"
Similar sound: These names share phonetic patterns with Jailen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have American (folk etymology) origins, giving them the same cultural heritage as Jailen.
Rhythm: Jailen is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.