These are Google's consumer apps. If a Google App is not listed here then it is either a Core App or may not be enabled in our environment.
When you sign in to Google, you may be presented with an agreement screen, regardless of whether you are using one of these apps. Learn more about the difference between Consumer Apps and Core Apps.
Please note that it is critical that you do not lie about your age if you are asked during the setup process, e.g. with Youtube or Google+. This risks disabling your access to all your applications including Gmail, and you will need to contact your college to resolve the problem..