An item you hold that emits light, lets say it'll help dark rpg's tremendously. 
 Items:
Candle - The candle blows out if you jump or reach a certain speed limit. 
Fire Torch - Same as the candle but much more stronger, and brighter, emits destructo wand idle. 
Glow stick - Emits a green glow, but no flare. Its gets dimmer over time. 
Flare - Very bright, red, and runs out after around 15 seconds.