This website allows you to choose educational videos (think Khan Academy, National Geographic, a TEDTalk, a read-aloud) and then allows you to pause the video they are watching, and you can add in multiple choice questions to ensure their understanding and comprehension. There are examples on their websites of how teachers used Read-Aloud books and multiple choice pop-ups to check-in on understanding. I personally envision using it for read-alouds - and you could tailor this to be a “guided” reading - tailoring your questions to the levels of your students and sending differentiated versions.
Free.
Here is a Step-By-Step Guide!