I am so happy to share these new releases related to font size changes in Pie, Bubble, Funnel and Scatter Chart!
Adding examples of each to have a look and try it.

Steps to change Label display In Pie Chart:

• Select Pie Chart from the Component Tree.

• At Labels, choose to hide labels or show them (either around the chart or in the legend).

• At Label size, use the drop-down to select a font size for the labels.
  

• Select the check boxes to Show values, Show percentage, or to show both. 
  
• Click Save.
  
  
  Steps To Adjust Label Font Size in Funnel Chart.
  
  
• Select Funnel Chart in the component tree.
  
• At Label Size, use the drop-down to select a font size for the labels.
  
• Click Save.

        Changing legend size, X,Y, and Z axis font & Title size of Scatter/Bubble Chart.

• In the Component Tree, select Scatter/Bubble Chart.
  
  
  
• On the Properties panel, at Legend select the box next to Show legend to show the legend.
  
• At Legend Size, use the drop-down to select a font size (Small, Medium, or Large.)
  
  
  
• On X axis & Y axis Properties, at Tick Label select the box next to Show tick Labels.
  
  
  
• At Label Size, use the drop-down to select a font size (Small, Medium, or Large.)
  
• On X axis & Y axis Properties, select the box next to Show axis Title.
  
• At Title Size, use the drop-down to select a font size (Small, Medium, or Large.)
  
  
  
• On Z axis, Bubble Labels dropdown select if you want to display the value or the label name.
  
• Then select the Label Size from the dropdown.
  
  
  
  
• Click Save.