Hi Kimi5564, 

You might want to look into the Purchases or Sales by Class Detail. These reports will show transactions that are categorized per Class. 

Just type in the Search field, Purchases (vendor transactions) by Class Detail or Sales (customer transactions) by Class Detail. 

With regards to your feedback, I'll personally send this to your Product Development Team that you like to add a Class column in customizing reports. 

I'll be here if you need anything else.