I personally think that Kelly for boys is perfect for a comeback (it's stayed steady for boys for the last several years while dropping for girls, and as of last year was 'only' more popular on new baby girls by a 5:1 ratio--about the same as Taylor, Skyler/Skylar, or Emery), but I bet there are even more options for parents who want a boy Kelly, but want to play it a bit safe.
- Kelados (KEL-ah-dos, [ancient] Greek)--"roar, shout"
- Kelaiah (kel-AY-ah, kel-EYE-ah, [Biblical] Hebrew)
- Kelemen (KEL-eh-men, Hungarian)--form of Clement
- Keld (KELD, Danish)
- Kelian (kel-YAWN, French)--from Irish Cillian, poss. "church"
- Kellen (KEL-len, English)--prob. a shortening of the Scottish surname McKellen ("son of Alan"), or an unusual Anglicization of Irish Caolán, "slender". Also spelled Kellan.
- Keller (KEL-ler, English [surname])--from German, "cellar", or poss. a shortening of Scottish surname MacKeller ("son of Hilary")
- Kellett (KEL-let, English [surname]--prob. from Old Norse kelda, "spring, well". Also spelled Kellitt.
- Kellner (KEL-ner, English [surname])--prob. occupational surname for a potter (or anyone else who used a kiln). Also spelled Kelner.
- Kelson (KEL-son, English [surname])--prob. Anglicized from Nordic surname Kjellson/Kjeldsen, "son of Kjell/Keld"
- Kelston (KEL-ston, English [surname])--prob. "calf-farm" or Cealf's farm"
- Kelvin (KEL-vin, English)--from Scottish river-name, poss. "narrow river"