The "Opening" (default since iOS 7) and "Reflection" (default for iPhone X and later) are the most recognizable [35].
There are three main categories of "call sound effects" on iPhone: iphone_call_sound_effect
While on a call, you can play audio from any app (like Music or a soundboard), and the recipient will hear it mixed with your voice [15]. Watch how to enable audio sharing during your live calls: The "Opening" (default since iOS 7) and "Reflection"