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"
"may Jehovah add"
"peace"
"growth, abundance, increase"
"the metal copper"
"one who strides, walks with purpose"
"pillar, support"
"God is my illumination"
"strong, powerful, prosperous"
"little fire (via Aiden root)"
"dark one"
"world ruler"
"small flock, family group"
"goddess of night, primordial deity"
"fire brand, flaming sword"
"geographic name from ancient Gaulish"
"lord, prince"
"little Hugh"
"hollow"
"slender, narrow"
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.