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"
"elevated, sublime, lofty"
"new settlement"
"hollow"
"marshland meadow"
"geographic name from ancient Gaulish"
"modern invented name"
"king's settlement"
"one who burns, charcoal burner, distiller"
"variant X-spelling of Zane"
"hunter"
"steward, household manager"
"God is perfect, Yahweh is upright"
"son of Hugh"
"flourishing, like a flower"
"the free one, freedom"
"town of stone"
"talented, handsome, outstanding"
"God persists, God will prevail"
"who is like God? (Michael, from Hebrew Mikha'el)"
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.