Kahoot lets us build fun quizzes. Students use iPads to join the game. You can create flashcards for review. You can also embed videos and use Kahoot as part of the teaching process, or students can create review games to share. There are so many worthwhile ready made quizzes that you can edit if desired.
Zaption lets you embed questions within the video. Students can't move forward in the video until they can correctly answer the question.
Readworks provides over 1,800 K-8 non-fiction and literary reading passages, each with a research based question set to support student comprehension that can be searched by grade level, lexile, and/or skill/strategy.
Wonderopolis Explore the wonder of the day with video, wonder words, and embedded quizzes. Post a wonder to Edmodo for a class discussion. http://www.edudemic.com/how-to-make-the-most-of-photo-feeds-in-classroom/