Silly idea for a racial, as we already have 'low light vision', but perhaps there could be a bioluminescence trait? For example, a race that has a light source or flame on its tail, or the skin, or tattoos, etc.
Essentially it would be a lantern, maybe with a different color, maybe not, that is powered by energy. Which can be great, but I can see it backfiring if you have it active while swinging a heavy weapon around.