To my knowledge, there is no book that has only offical cases and it wouldn't really matter because firms change the cases they use all the time, since they inevitably get out.
Instead, you should use a range of resources, from published books, firms' websites, and school's case packs. Practice with a mix of case types and understand whether you'll be doing interviewer- or interviewee led. Also important to practice with someone who knows from experience what the expectations are and how to compare your performance with those standards, not just someone at your own level of experience.
This will develop your skills to the level where you can succeed no matter what they throw at you.
Hope this helps. Happy to discuss more!