River sits next to 3 phonetic neighbors — Ryder, Silver, and Riviere are the closest matches by sound. Most share River's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"flowing body of water, stream"
"Lord"
"rock, stone"
"rejoice, keeper of the keys"
"brave as a wild boar"
"son of the south"
"little hollow, small meadow"
"Jehovah is God; the Lord is my God"
"my God is Yahweh"
"gracious, mild"
"Finnish person, Norseman"
"man from Lucania (region of Italy)"
"one who hunts"
"son of Hudd"
"of Mars, warlike"
"God has healed"
"belonging to Julius"
"ruler of the elves"
"gentle, beloved"
"healer"
Similar sound: These names share phonetic patterns with River — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old French origins, giving them the same cultural heritage as River.
Rhythm: River is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.