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"
"descendant of Ógán"
"that which is yet to come"
"my messenger, my angel"
"bold journey, brave traveler"
"religious official, one who performs sacred rites"
"green gemstone"
"short form of Bradley or Bradford"
"warrior spirit"
"the river that swallows all rivers (from Zaire/nzadi)"
"dark one"
"powerful, mighty"
"dwelling near the church"
"emperor, ruler, caesar"
"bright star in Aquila"
"place of protection and calm"
"third son with divine grace"
"eldest son (Na'vi fictional language)"
"friend of the gods (Germanic tradition)"
"my father is peace"
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.