Regan sits next to 4 phonetic neighbors — Reagan, Keegan, and Brogan are the closest matches by sound. Most share Regan's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"little king, of royal descent"
"thankful, he will judge"
"victorious"
"brave warrior (via Wyatt)"
"modern variant of Dawson"
"modern American coinage"
"dark one"
"bright fame"
"elevated, sublime, lofty"
"bouquet, bunch"
"appointed by God"
"broad valley, wide clearing"
"legendary king of Phrygia, golden touch"
"modern invented name with phonetic appeal"
"sea warrior, sea spear"
"imperial authority"
"young, youthful"
"firm, steadfast"
"Italian form of Henry"
"powerful, compassionate (fictional origin)"
"one who burns, charcoal burner, distiller"
Similar sound: These names share phonetic patterns with Regan — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Irish Gaelic origins, giving them the same cultural heritage as Regan.
Rhythm: Regan is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.