For big game (deer, moose, elk), varmint, and predators, a red light is best. They do not have red-registering light cones in their eyes, so they are incapable of seeing the color red.
Red light, coyote hunting dogs, and the best coyote baits will make taking out these varmints very easy.
But if you’re going hog hunting, green light is best. Their eyes are less capable of registering green than white or red.
Just make sure that the light that you use isn’t too bright. Even if they cannot recognize the color, if the light is bright enough, they would run away all the same.