Some selected frameworks I played with.
AVFoundation
AVKit
Contacts API
CoreAudio
MapKit
MessageUI
PushKit
QuartzCore
SafariServices
Social
CoreFoundation
WatchKit
TVKit
CoreTelephony
Twitter SDK
WebKit
Alamofire
SwiftyJSON
WebRTC
Sofia SIP
MediaToolbox
QuartzCore
Facebook SDK
Fabric & Crashalytics
Parse SDK (RIP 😭)
Google SDK
AFNetworking
ASIHTTPRequest
RestKit
Urban Airship