Does every particle have an antiparticle? So far, every particle that has electric charge has a distinct antiparticle. But the answer is not so clear for neutral particles. For example, there is no distinct antiversion of the photon (which has no charge), i.e., an antiphoton. Some would say that the photon is its own antiparticle, which seems more like avoiding the question than answering it (i.e., does being your own best friend mean you have no friends?).
