here goes mine:
djokovic’s forehand (watch the 07 us open final and its not hard to notice how massive of a change it was)
wawrinka’s forehand (no need to comment here)
nadal’s forehand
federer’s backhand '17-'18 (that one is questionable, maybe its more due to the larger racquet frame)
People keep forgetting that Roger changed to a larger racquet head as early 2014. 2017 onward was definitely a technique change, taking the ball much earlier.