Nicolas Nadeau's triple Axel is gigantic (he's 6'1" and has a large build), and he has so much power when he jumps into the air. He had performed a 3A-3T just last week at the Quebec Summer Championships ( https://vimeo.com/284513182 --- you'll notice that the top of his head goes past the camera's frame) which earned him +3 and +4 in GOE ( https://resultats.patinage.qc.ca/wp-content/uploads/2018/08/22_det.pdf ), and it's even more impressive when seen in person!
The most obvious, Yuzuru and Han Yan were already mentioned (3A to die for!), so was Nic, so the only other 3A that I really appreaciate is Misha Kolyada's! When he's on, he's on!