The ONLY add-on I've found that downloads HD videos. Works great on nearly everything, though I've run into one or two videos that it couldn't download.

Update 7/23/20: Software has been updated to change the way it activates for the pro version. Only people who bought in the last 12 months get to keep using it. I paid for pro 15 months ago so would need to pay again but I will not. Dropping my rating considerably for this.