My helmet has a built-in red LED in the rear, two modes of flashing or solid on. Not super bright but noticeable. I don't rely on it, mainly on the taillights on my bike, but use the helmet light to augment my other lighting.

As far as a white light on front goes, I have a light made to clip on the visor of a ball cap which easily clips onto my helmet visor. Again, it's not super bright, wide field lighting, but just augments my bike's headlight and gives me a little more visibility as well as allows me to look down & see my bike if I need to.