You can make drag and drop matching exercises by using the drag and drop function all browsers possess. Look:
I just dragged and dropped the Moodle icon into this forum message. (Actually, I'm not a 100% sure that that kind of drag and drop works on all browsers but it does on Firefox. Inside a Hot Potatoes exercise drag and drop always works in my experience.)
Here's an example: Pronunciation of the -ed ending
Thanks to Martin Holmes who told me how to do this years ago.