Loved the Czapek Rattrapante already, but that one is too big for my wrist. Other than those two, I think AP is doing a great job on their openworked royal oaks. And FP Journe also did a few nice (semi-)openworked pieces.
There are skeletonized watches where people would take a normal movement and remove as much material as they can but the movement has never been conceived to end up like that. End result often look a bit weird. On the other hand, when a movement had been ...