In English-language chess commentary, "Harry" and "Gary" refer to the g pawn and the h pawn on the g and h files of the chessboard. Because Harry and Gary are on the kingside, which is the side to which both players most often castle, Harry and Gary are extremely important pawns that defend the king, and also like to lurch forward to attack the opponent's king. Harry and Gary are the pawns most often referred to by anthropomorphic names, although the f pawn is also named "Freddie" and gets mentioned to a lesser extent.
Note that these names contradict the official pawn names promulgated by worldwide chess organizing body FIDE, which no one pays attention to. According to FIDE, these pawns are supposed to be called Gustav and Hector, but again, no one pays attention to what FIDE says.