Psychology Through Diagrams, by Grahame Hill: my top recommendation for a revision guide, but it is not IB specific
Crazy Like Us: The Globalization of the American Psyche, by Ethan Watters: really interesting about how western views and practices of various disorders (anorexia, depression, schizophrenia, PTSD) have influenced non-western cultures. You can check this out of the ISS library.
Cognitive Level of Analysis:
Predictably Irrational, by Dan Ariely: decision making is a cognitive process, and Ariely examines it from a behavioral economist’s viewpoint. Easy & enjoyable to read, written in a non-academic style. You can check this out of the ISS library.
Discovering Psychology: with Dr. Philip Zimbardo