Sonny sits next to 4 phonetic neighbors — Sunny, Benny, and Ronny are the closest matches by sound. Most share Sonny's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son, young boy"
"keeper of the pantry"
"steadfast defender"
"appointed by God"
"hunter, one who hunts"
"wealthy"
"messenger of God"
"glorious fighter"
"rest, repose"
"battle strength"
"son of the fair one"
"the crowned one"
"descendant of Ceallachán"
"great brightness, sea circle"
"light, illumination"
"bane, destruction (war god)"
"angel; messenger of God"
"Lord, have mercy (liturgical)"
"from the bridges"
"Currency"
Similar sound: These names share phonetic patterns with Sonny — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have English origins, giving them the same cultural heritage as Sonny.
Rhythm: Sonny is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.