All the resources I have gone through are quite old and don't provide the complete set of names for a launch image. Like this.
I am aware that launch image set take care of that, but while using it for a full screen UIImageView, it doesn't work. So I am going by the old way.
This is Apple's link for the list of devices and their resolutions. Screenshot :
I have managed to get most of the names other than :
iPad Pro 10.5 inch
iPad Pro 12.9 inch
iPad Pro 12.9 inch 2nd generation