What pitches they've seen, what they're swinging at and what they're doing when they make contact
At this point in the season, this stuff isn't going to tell us all that much. The sample sizes are small, meaning a few hits going into one bucket or another, or a few swings going into one bucket or another, can still significantly affect what has already happened and also affect what these numbers might look like next week (particularly for occurrences with lower probabilities). And I'm not going particularly granular here, sticking with essentially three sets of data from Fangraphs that are pretty broad.