App Inventor offers some strong multimedia possibilities. You can add audio, video, and images to your apps to make them more engaging. This is an essential component of many apps that developers create, so having experience with this will certainly be helpful later.
Your users can select existing media with the ImagePicker and create new media with the Camera and Camcorder.
At this point, your toolkit should be fairly robust for creating many different kinds of apps. Going forward, a good learning activity is to begin creating apps outside the parameters of what you have built to this point.