Lens hoods are not only used during the day, but are also necessary at night. If you shoot a long exposure, there will be a lot of light coming in from all directions. A lens hood can help to prevent other unwanted light from entering. Apart from that, another function of the lens hood is to protect the lens from impacts.
6. Spare battery / vertical grip
A spare battery is needed when you take photos for a long duration. Don't let yourself stop because the battery runs out. If you want something practical, you can use a vertical grip, an additional accessory on the camera body that is equipped with a battery. Apart from that, you can take portrait photos as easily as taking landscape photos.
7. ND filters
ND filters can help to reduce the intensity of light entering the camera, their function is like the sunglasses we usually use. Even at night, if you don't use this filter, if there is light near you, there is a risk of over exposure.
8. Smartphones
Smartphones can help you in shooting, for example a timer application to find out how long the exposure time is. Or also other applications such as maps, to help you find your way home.