Brennen sits next to 4 phonetic neighbors — Brendan, Brennan, and Brandon are the closest matches by sound. Most share Brennen's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"prince, king"
"the color blue, sky"
"from Luca, of the light"
"mortal being"
"sky, heaven (root)"
"variant of Jason (healer)"
"God is my help, my flock is God"
"clear, tinkling sound"
"descendant of Braonán (moisture/sorrow)"
"acquired, craftsman (via Hebrew Cain/Kaine)"
"of Rome, strength"
"to shine, emit light"
"to heal"
"son of John"
"from Milan, middle of the plain"
"Yahweh is righteous"
"slender youth, young warrior"
"supplanter (via Jacob/Kobe etymology)"
"creative elaboration, bold individual"
"one who tends a gate or hatchway"
Similar sound: These names share phonetic patterns with Brennen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Welsh/Celtic origins, giving them the same cultural heritage as Brennen.
Rhythm: Brennen is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.