A Duometre Spherotourbillion by Jaeger-LeCoultre. Not only does it spin freely on one axis, but it also tilts at 20 degrees, freeing it from all gravitational effects.
Whether or not that actually changes how precise the mechanism is is up for interpretation. Regardless, it’s extremely intricate, and also very “rare” in the sense that it is not easy to design or build one of these tourbillions.
That’s probably why this watch garners a $200,000 price tag.