Hello Stefan,
This code lines should output the labels of the aligned cameras:
aligned = [camera for camera in chunk.cameras if camera.transform and camera.type==Metashape.Camera.Type.Regular]
for c in aligned:
print(camera.label)
If you need also to distinguish between some groups of cameras, you may consider camera.group value (providing that the cameras are put to some groups in the chunk contents), or check camera.photo.path - the path to the source images.