I just learned through a Tweet from Stanford History Education Group that they have made their library of history lessons and assessments available to view and download for free. You need to open an account on Stanford History Education Group in order for you to be able to download these materials. I spent some time going through those resources and found them worth the shout-out here.
The resources cover both world history and the United States history. They particularly feature “history lessons and assessments that ask students to evaluate pieces of visual art, including paintings, illustrations, engravings and political cartoons, as historical evidence”. Each history lesson comes with a number of downloadable materials including teacher and student materials, PowerPoint slides, and original documents. Some of these materials are also available in Spanish.