I'd rather not go into this type of division as it is very difficult to guage if a coral is rare or exotic. What may be super nice, rare or exotic to me may be just another coral to another person.
Rare and exotic especially for corals depends on the number of such exotic and rare pieces that the LFS brings in. For example, you se emany different colour morphs of corals in the states that you don't normally see here but in the states, quite a number of reefers and many LFSes actually stock those corals.