hey!
the best sample cases are not public, but you can reliably find good practice material in three places: the INVERTO career page (they share a short example of a procurement case), the BCG operations cases (very similar style), and general procurement/operations cases on platforms like here on PrepLounge. INVERTO cases are almost always about sourcing strategy, cost reduction, supplier selection, make‑or‑buy, or supply‑chain optimisation, simple, data‑driven, and very structured.
Alessa