Usual Nickname, Unexpected Name--Kelly

Kelly is, of course, a surname-turned-given-name, but since it's been surpassed by Kellan & Kellen for nearly two decades now (and by Kelvin for even longer, although it's been on the decline since the 60s), it's more likely that any male Kellys you meet today are using it as a nickname.

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"