Honestly if you're getting into PS2 you're in for a treat man, the library is stacked. Start with God of War, Shadow of the Colossus, GTA San Andreas and Kingdom Hearts, those alone will blow your mind. Metal Gear Solid 3 and Ico are also absolutely worth it. Whatever you do just make sure you download from a trusted source to avoid any corrupted files ruining the experience. You really can't go wrong with PS2 classics!