Harry Greb deserves a mention. It's too bad that there aren't any footage of Greb in his prime. Which modern fighter would be the closest to Greb?
Just like to add Vicente Saldivar, Myung Woo Yuh, and Brian Mitchell to the list. These guys don't get mentioned enough but they also have great skill while pressuring their opponents.
Armstrong and Pryor were the first two people who came to mind. I don't think anyone mentioned Emile Griffith. He kind of abandoned this style after Paret, but used it effectively previously.
Griffith became, or evolved into something entirely different from a pressure fighter after Paret. In the place of the enthusiastic, swarming slugger type came the adaptable mechanic/technician...best evidenced in the first Tiger fight...10 lbs lighter than Tiger, upper body about the same as Tiger's, yet he boxed...boxed beautifully, and to his detriment regarding fan popularity, he became a cautious fighter....applying pressure, but not really swarming vs the boxers...the Archers, etc., and boxing effectively like vs Tiger.
I just watched calzaghe-Lacy again, and it never fails to impress me...and JC did have an element of Greb in his style. Calzaghe gets nowhere near the respect that he deserves here IMO.