*deep breath*... you can add links, notes, images, PDFs, YouTube videos, Tweets, Facebook posts, Instagram posts, links to Google or Dropbox Documents, Soundcloud tracks, Spotify playlists, Google Maps, Vimeo videos, Dailymotion videos, Slideshare slideshows, GIFs, Flipgrid responses, Screencastify recordings and more! Phew! 

This collection will show you all of this in action, and see here for more on adding content.