Johnny sits next to 5 phonetic neighbors — Bonnie, Lonnie, and Ronnie are the closest matches by sound. Most share Johnny's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"God is gracious"
"dark, from the Adriatic"
"safeguarded, protected by God"
"grace, favor"
"divine judgment"
"veena; musical lute instrument"
"fortified battle"
"peaceful ruler or eternal ruler (from Erika/Rika)"
Similar sound: These names share phonetic patterns with Johnny — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Hebrew (Yohanan via John) origins, giving them the same cultural heritage as Johnny.
Rhythm: Johnny is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.