There is a way to group your products and view the product data by brand, size, color and etc on the Product Stats page.
Step 1: Go to Main Menu > Products > Product List where you're able to edit the Group column:
Optional: You do have the option to Bulk Upload your Group names. See: How to Bulk Import Product Costs & Info.
Step 2: Once you have updated the proper Groups go to Main Menu > Products > Product Stats. Then use the Smart Search filter to select the desired Group name and date.
NOTE: Remember Product Stats main function is to show stats on products that have made sales in your chosen date range. So choose a WIDE date range that includes sales on all products in that group, if you want to view all your products. Alternatively, if you choose the past week for example, your Smart Search results will display only those in the Group that have made sales in the past week.