Link's Blacklist is a fan project -- the idea is for one artist to choose one single enemy from the multitude of enemies featured in all of the Zelda games, and draw it to the best of their ability. There's some truly incredible stuff among them.
I'd say the various iterations of Ganon make up some of my favourites. The above effort really does a good job of representing the feel of Twilight Princess.
This representation of Ganon looks as though it could be a Dark Souls boss, which makes total sense considering that the original Zelda shares a lot of that game's DNA.
I remember Demise from Skyward Sword being a genuinely intimidating force. This does a good job of representing that.
Ganon from Ocarina of Time also looks incredible. That moment, when he rises from the rubble of the tower, may be one of my favourite of all time.
Check out all of the artwork here.