The Argentiums in general. Martial Arts and Aura Manipulation is basically their thing, not to mention why they're so influential. They're not afraid to square up against wild Pokemon if they have to. Their team aren't the only well-trained battlers at their disposal.

Side note: Everyone that Elio personally knows or has some connection to - rivals and archenemies included, can throw hands as well. They would even fight others as their 'mons battle. Thrill of the battle and all that jazz.