You can download 48 2D drawings and 3D model based definitions in PDF format on this website. Each page contains 4 free models and drawings. All these are mechanical parts and you can use them to practice.
An isometric view of the 3D model is always placed on the upper right corner to facilitate easy understanding of the 2D views. Of course, all these will be unnecessary when the industry fully moves to the model based definition in the future. We have many legacy components and information/drawings that still follow 2D drawings.