Kullen sits next to 5 phonetic neighbors — Cullen, Collin, and Kullan are the closest matches by sound. Most share Kullen's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"hill, ridge, small summit"
"fury, divine madness, inspiration"
"gift of God, godlike"
"son of Rawlin"
"modern American creation blending Terrence with melodic -ion suffix"
"from Hesston (place name)"
"may God protect"
"the sun, solar light"
"army, host"
"modern nature compound name"
"oak tree"
"he will judge"
"protector of people"
"belonging to God, of the Lord"
"craftsman, smith"
"from the settlement clearing"
"modern invented name"
"victory of the people"
"the sparrow bird"
"keeper of the keys"
"slender, narrow"
Similar sound: These names share phonetic patterns with Kullen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Scandinavian origins, giving them the same cultural heritage as Kullen.
Rhythm: Kullen is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.