Wakelet is a great tool for making collections and saving bookmarks, text, pictures, videos and other content. You can register as a student or a teacher and when you create your first Wakelet collection, you can share it with others. It also has options to collaborate on a Wakelet collection together with other people, for example your class.
Here is a short tutorial how to sign up and start using your Wakelet. In Croatia, we use educational mail given by our school and register with our skole.hr extension.