Kelly sits next to 4 phonetic neighbors — Kelley, Kell, and Kellan are the closest matches by sound. Most share Kelly's Irish-rooted cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"bright-headed warrior"
"elder, one of authority"
"God is salvation"
"the greatest"
"green river, fresh water"
"path to the sea"
"modern invented name, valley dweller (from -den suffix)"
"modern invented name"
"safe harbor, place of refuge"
"son of Jack"
"light, illumination"
"forest guardian, one who patrols"
"lime tree hill"
"elm grove"
"young dog, whelp (strength and loyalty)"
"admirable, hawk-like"
"of the sea (possible etymology)"
"to listen, to spy out"
"warrior, fighter"
"eagle"
Similar sound: These names share phonetic patterns with Kelly — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old Irish origins, giving them the same cultural heritage as Kelly.
Rhythm: Kelly is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.