AppsCenter is the first plugin that gives you the ability to access all the apps you want right from the Notification Center.
You have tons of Settings that allows you to organize your apps or slightly customize the appearance of the widget. For example, you can toggle labels for icons and the scroll indicator, or sort apps by name or category. You can also decide to put all your apps inside the widget, by enabling the correspondent option from Settings. Otherwise, you can choose an unlimited number of apps from the one you have installed.
You need to enable the widget from Settings > Notifications before seeing it in the Notification Center.
Further options are available from your Settings app
NotificationCenter addons can be configured from the Settings app, in the Notifications panel