I use Google Classroom with Blendspace and Thinglink. Depending on what we are currently working on in our curriculum. I mostly use it with Science and Social Studies. We are learning about Matter and Landforms. I can easily find lesson or even create lessons on Blendspace or Thinglink and add the assignments into Google Classroom.
Here is a Thinglink that I created on Plant Life Cycles. My students have really enjoyed getting to learn about Plants by using this awesome site. All you do is insert an image and you add tags on the picture that has videos, websites, articles, songs, books and more. Students work their way through each tag on the image and begin to learn. You insert a quiz or assign a journal or activity to complete the lesson.