This is a "free game-based learning platform." Kahoot features individual or team styled multiple choice quizzes and surveys that can be created and/ or shared for others to use. I use this resource to create excitement about Eureka Math Vocabulary. My students love it!
Readworks.org is a free and great website to find reading material and questions for a variety of skills and content. I use it for homework and writing assignment sources.
This website is great for designing presentations. I have used it to present information to my class, but I have also taught students how to use it so that they can present information as well.
This website is a free/ premium math website. The free version is great for math assignments. However, if you can talk your school site into the premium account, there are many great facets to explore. We use the assessments to evaluate students learning and base our reteaching and differentiation on that data. There are inquiry based activities for students. There is an instructional resource based around Common Core Standards and many other ways to facilitate math learning.