There are about 78 types or species of whales, though this number ranges from 78 to 90 depending on the source. I believe it might be the Fin Whale that has the largest population size up to date. The Omura's Whale is a very rare species that is close to extinction. Other than that, the Baleen Whale is also close to extinction. I'm not absolutely sure, but I hope this helps at least.
