I can't speak to specific preplounge cases. However, I can share my favourite resources for case interviews while I was going through interviews. You should be able to find all of these online quite easily:
1) Company websites: McKinsey, BCG, Bain, Oliver Wyman, etc. all have excellent examples of cases online. These are excellent as they come straight from the source and are generally a good indication of how cases at a specific company are structured
2) ESADE business school case book: This book provides some excellent tips and then dives into some great beginner/intermediate cases. In the second half of cases in the book there is a drop in quality, but it was still one of my favourite resources when practicing.
3) MIT Sloan 2011 casebook: In my opinion the best case book released by a business school I have seen. Excellent cases of ranging difficulty from actual companies, which most closely resemble actual cases you will receive while interviewing.
Hope this helps!