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"
"Yahweh is gracious"
"talent, ability, brilliance"
"named after father"
"divine gift"
"bear king"
"imperial authority"
"shepherd, sheep herder"
"white, fair-complexioned"
"firm, steadfast"
"one who is a lord or master"
"of the night"
"white settlement, white farm"
"man of the forest"
"lunar, bright as the moon"
"a group of birds, especially quail"
"beauty, goodness"
"prince, ruler"
"cutting edge of a sword or tool"
"gentle wind"
"sun"
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.