Flex contains many core lists to enable immediate use of the system for specific business situations. You can find the lists in your system by going to Site Content.
These lists perform different functions and, therefore, contain specific features that relate to that function. For example, an Opportunity list item has a different purpose than a Meeting or a Task item will. To see the features that are inherent in the core Flex lists review each list section.
Every customer site can have their own custom lists added to a SharePoint Flex template.
See the section on Custom Lists for specific details on the types of lists that can be created and added to your SharePoint Flex system.