You can use this Swift 5 code to play system sounds:
// import this
import AVFoundation
// create a sound ID, in this case its the tweet sound.
let systemSoundID: SystemSoundID = 1016
// to play sound
AudioServicesPlaySystemSound(systemSoundID)
The most up to date list of sounds I could find are here.
And this is what they all sound like:
https://www.youtube.com/watch?v=TjmkmIsUEbA