Best Pre-made Educational Content Resources

When I was a classroom teacher, I recall many anxious afternoons and evenings spent scrambling to come up with quality content for a lesson I had to do the next day. Even when I was planning further ahead, it was a stressful, excruciating process to line up resources that I could use for various topics and standards. Now, more than ever before, an abundance of free resources exist that we can conveniently use the next day. In fact, so much exists that it is difficult to sift through it all. Here is a list of sites that I have found to offer quality materials. I wish I knew of them when I was teaching.