Just found this and thought it rather interesting and adds just a little something more to the already great answers posted.
The following is from the Flashlight University: LED Colors and Uses.
White: Great for all around, every day illumination.
Red (630 nm): Red LEDs are do not appear as bright to the human eye as white LEDs. If your eyes are night vision adjusted, it’s a good idea to use a red LED to navigate your way in the dark so you don’t ruin your night vision. Red light is also great for camping if you do not want to wake your neighbors with a bright white light. Red light is the universal signal for attention, so it is a great thing to have in emergencies for signaling and safety.
Green (525 nm): Green LEDs are useful outdoors. Many hunters claim that the green light attracts deer and other wild game, and the green light will not scare away fish, deer, and other game like a bright white light will. The green LEDs also have a longer run time than many other colored LEDs.
NVG – Night Vision Green (495 nm): NVG LEDs, along with red LEDs, are useful for preserving night vision. NVG colored LEDs are useful for military pilots as well, who have special equipment that is designed to work with NVG lights.
Blue (470 nm): Blue LEDs are useful for pilots and other personnel who need to read maps at night. Other colored LEDs (such as red LEDs) will not work for map reading because it will wash out red lines. Blue LEDs are also used by police and crime scene investigators because it will make blood and bodily fluids visible that are usually invisible to the naked eye. Blue light is the only light that can cut through fog, which is why it is widely used for fog headlights.
It should be noted that most animals cannot see true spectrum green and blue can be used for tracking wounded animals.
The following is from Voidhawk Flashlights: The best 3 color RGB Tactical Flashlight available today!
Red: Coming in at 630 nanometers the Voidhawk RGB Tactical Flashlight uses the perfect Red wavelength for tactical applications such as map reading, hunting, or any nighttime activity where you want to save your night vision.
Green: Registering at 535 nanometers the Voidhawk RGB Tactical Flashlight uses the perfect Green wavelength for the human eye. Our eyes are most sensitive to green light which makes it perfect for navigating the dark. Green light gives you a high illumination value without causing you to lose your night vision. Most animals cannot see true spectrum green light very well so it does an excellent job of lighting up a field without disturbing the game.
Blue: Using a royal blue 465 nanometers the Voidhawk RGB Tactical Flashlight uses the perfect blue light wavelength for tracking blood trails of wounded prey without sacrificing your night vision. Blue light is also excellent for fishing at night as it shines straight through the water without producing any glare, it’s as if the water isn’t even there!
Black light (blue) I find great when in a tent setup with others and you want to find something without a bright light to possibly wake up someone else.