Emotions, actually. Rage, Love, Fear, Courage, Hope, Avarice (Greed), and Compassion. Green and Yellow have the same powers but the others have different abilities. The Orange Corps is the most interesting. Being Greed, it has only one actual person running the whole thing and he holds 1000% power and creates duplicates of the people he's killed to do his bidding.
As someone else pointed out, there's also black and white for life and death but that was just a temporary thing and really doesn't pop up that much anymore.
its pink and white, but on every lantern when i do their black or white on their costume, its matched to their ring color, so for green lantern i use a soft yellow or green instead of light blue as i would normally, and with fatality its light pink because of the rest of her costume. the logic is that white and black best take on colors surrounding it, so it's actually white but usually appears slightly pink because of all the pink around it. im actually using light pink but it is indeed supposed to be white