Rhen sits next to 5 phonetic neighbors — Ren, Wren, and Rhett are the closest matches by sound. Most share Rhen's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"flowing river, running water"
"beloved of God"
"from Kansas City"
"bold, brave counsel"
"modern nature compound name"
"who is blessed"
"hollow, vain (from Latin Cassius)"
"arms (of God)"
"lasting, persistent"
"upright, righteous"
"strength, exalted one"
"cushion (alternative Irish etymology)"
"love"
"derived from Terentius, possibly tender or gracious"
"Lord, master"
"young goat"
"my help, my helper"
"bear"
"may God protect"
Similar sound: These names share phonetic patterns with Rhen — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Celtic origins, giving them the same cultural heritage as Rhen.
Rhythm: Rhen is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.