Are all flavors known?

Especially among types of fruit there seems to be a lot of variety. If there were an alien planet with its own native fruit trees would we be able to think of what those fruit trees might be like without ever setting foot on an alien planet?

…or if we had never found the new world, would we be able to guess at every taste possible?

Chocolate is pretty modern. Might there be five more flavors that would be that impressive that we don’t already know about?