I haven't seen wisent, vicuña, lesser rhea, or common gundi, although that's because these are common in Europe. Also, I'm missing griffon and Rüppell's vultures.
I suppose it depends on whether one is referring to the Great and Scalloped Hammerheads, or the Bonnethead. The latter is somewhat common in the aquarium scene, but still not overly so. The other species are kept at only a small handful of institutions across Europe and North America. How common are they within the Asian countries where they're present?
Hammerhead sharks are quite rare in Europe. I've seen scalloped hammerhead at Biarritz aquarium. Only 4 aquariums in Europe have it. Great hammerhead in 9, never seen one.