Rei sits next to 4 phonetic neighbors — Ray, Rae, and Rye are the closest matches by sound. Most share Rei's Japanese cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"courtesy, respect, gratitude"
"priest"
"elevated, sublime, lofty"
"little king"
"royal town or manor"
"may God protect"
"gray, silver-haired"
"right-handed, skillful"
"rocky outcrop, tor"
"warrior (via samurai resonance)"
"associated with Al-Khidr, the immortal guide"
"powerful giant, cosmic force"
"apparent, visible"
"divine door (from Kobe, Japan)"
"son of Mart (Martin)"
"little fire (via Aiden root)"
"God is perfect, Yahweh is upright"
"related to Everett (brave boar)"
"youthful, downy-bearded"
"long-lived, permanent"
"builder, craftsman"
Similar sound: These names share phonetic patterns with Rei — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Japanese kanji 礼 origins, giving them the same cultural heritage as Rei.
Rhythm: Rei is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.