Vortex swirl,
Backside Clownface
Pixie Dolomite swirl
Furious ducking toe stall.
Those are the hardest ones I can recall hitting at the moment.
Flurricane bsos really isn't hard. The lack of difficult uptime makes it quite easy to link out of anything. For me personally, something with a much harder uptime is trickier to bsos, such as the furious ducking toe.