Sparkline

More important (and more useful) would be the ability to add JSON custom formatting following the exact API we already know and use within the SPO list functionality. This would allow granular (and dynamic) control of what appears within EACH field within a table. I also think you could apply this custom formatting at the field level within ANY visualization allowing you to have (for example) a scatter plot where certain dots (based on the JSON) are larger and a different color because they meet certain criteria outside the dataset being used to calculate the chart. For example, if a dot is associated to an item where the field [CRITICAL] is true, then color=RED.