There are a huge amount of methods to modify your car lights. You could use headlight covers to alter the shape of your lights and make them appear tinted. The headlight bulbs can be upgraded using HID4 (High Intensity Discharge) which make them appear a very bright white.
You can also upgrade your fog lights by changing the colour to something niche like electric blue. Some bulbs are available which flash several different colours.
You may choose to change the interior lights in your vehicle. The lights can be changed to another colour or added to different aspects of your car like the footwell or dashboard.
Undercar neon lights sit underneath the vehicle and light up the ground below the car. However, ensure the tubing is not on show and that these lights are only used when the vehicle is stationary otherwise you would be breaking the law.