It was difficult to pick a single favorite, but I think I go with this Druddigon:
Love the attack pose and overall artwork, the little shine in its eyes, the flying debris, etc.
As for some other favorites in no particular order for various reasons:
Oh, and I was surprised to see that Kawayoo did three different Druddigon:
Although I like the one from Ryota Marayama a bit more personally. Druddigon apparently has a lot of fierce artworks, although also these two mellow ones. 
Greetz,
Quuador