Unfortunately, the cases that are used for teaching are only available for individual purchase from the Harvard case store: https://hbsp.harvard.edu/cases/ They are not available for libraries to purchase.
Harvard Business Review contains some abbreviated cases. Depending on what you need you may be able to find a version in the magazine.
Alternatively, we have a subscription to Sage Business Cases. They offer full cases with instructor notes. If an instructor has a specific Harvard case that they like to use, the Sage team is very responsive and can help find a similar case in the Sage collection.
Sage offers full cases with instructor notes. They can also help identify the best cases for your course. Contact buslib@colorado.edu to get set up as an instructor.