Not talking about low blows, elbows, or head butts.:!: Talking about the slightly against the rules habits of very good fighters in gaining the upper position with holding, hand placement, and head/hand control to gain that extra advantage... Who comes to mind for you? Was watching some Emile Griffith, Roberto Duran and some Floyd Mayweather recently is the reason for the thread...:good
Lennox Lewis always held the back of his opponent's neck with his left hand and throw a right uppercut.
Hatton was great, Wlad is/was good, Ward (although he butts also) and definitely Ali. HWs seem to do this more since there is generally more clinching and they have long levers which get tangled easily. Master of the half-foul/ half-maul was surely Henry Armstrong. Honourable mentions to Sandy Sadler though, he was awkward to the point where he was fouling also.
Fritzie Zivic wrote an impassioned defence of dirty fighting, in which he argued that all the great fighters of history were dirty fighters, and that a well-executed thumb to the eye was a thing of sublime beauty!