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"
"marshland meadow"
"geographic name from ancient Gaulish"
"faith, religion"
"peace settlement"
"rye meadow"
"to offer, to announce"
"prince, ruler"
"powerful ruler, brave power"
"doctor, healer"
"apparent, visible"
"wise guardian warrior (fictional FFX character meaning)"
"creative variant of Tavian or Haven"
"spike, pointed"
"bouquet, bunch"
"small stream, narrow inlet"
"battle, spirit of battle"
"divine friend, friend of God"
"warrior in the field"
"modern American invented variant of Zayd"
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.