You gotta be cool to have swag. You can't be all loud and trying to bring attention to yourself. Asuma, Shikamaru, and Sasuke (can't stand him but it's true...) take it. Tobirama too he's got a cool quietness but real presence about him.
Gaara, Itachi, Minato, Kakashi, Darui, personally I liked Dosu during the chuunin exams, and orochimaru but not so much swag as a "calm serial killer vibe"