I think Qlassic Bois Margot, he is Simon Delestre'horse (number one ranked). He is a beautiful black stallion of high level jumping.
Ursula XII and Hello Sanctos I think. They are Scott Brash's horses, real champions!
All the horses of Edwina Top Alexander!! I would die to be able to ride of of her horses, and especially Itot du Château <3
Actually there is no A horse I dream to ride. I would just enjoy to sit on a horse of Grand Prix to discover the feelings!