P.S. If you have a specific PDF you are looking for (e.g., "Réduction des endomorphismes - méthode exhaustive"), drop the title in the comments—someone here probably has a link.

The curriculum for MPSI is dense. A typical "Méthodes et Annales" PDF or physical copy covers:

While sharing PDFs of old annales (exam subjects) is generally fine, be careful with full scanned textbooks (Monier, Arnaudiès, etc.). Support your library or buy used copies. However, instituts and académies often release free "extraits" that are gold.