1. UIKit: UIKit is the foundation for all iOS and tvOS apps. It provides essential infrastructure for building apps, including classes for managing user interfaces and for managing the flow of data in apps. Examples of UIKit components include windows, views, controls, and the app’s main run loop.
2. Foundation: Foundation is the core framework of the Cocoa and Cocoa Touch frameworks. It provides basic classes and data types for working with strings, numbers, dates, collections, and other common objects. Examples of Foundation classes include NSObject, NSString, NSArray, NSDictionary, NSDate, and NSNumber.
3. Core Data: Core Data is a framework for managing data objects in an app. It provides an object graph and persistence layer for managing data. Examples of Core Data classes include NSManagedObject, NSManagedObjectContext, and NSPersistentStore.
4. SpriteKit: SpriteKit is a framework for building 2D games and other graphical applications. It provides classes for creating and managing sprites, animating them, and handling user input. Examples of SpriteKit classes include SKNode, SKSpriteNode, SKAction, and SKScene.
5. Core Animation: Core Animation is a framework for animating views and other UI elements. It provides classes for managing layers, animations, and transitions. Examples of Core Animation classes include CALayer, CAAnimation, and CATransition.