One of the great features of whmcs is the promotions, we typically give these to our sponsors to help track referrals. I generally have to make a few new promotions every month. We have around 60 packages and every time I make a promotion I have to manually check each box which is a pain.
It would be nice if each product group in the Applicable Products/Services list had a "Check All from this group" button, as well as a "Check all products" at the end of the list.
An alternative option would just be using the duplicate method just like how you can duplicate a product.