Instead of trying to find some kind of amber side lights for my bike, I bought some lights for the wheels which I turn on during the dark. They're all over Amazon. I feel it gives me better side visibility with having two large colorful rings of light spinning around than by putting a couple of small amber lights on the front or something. Plus I have reflective tape placed at strategic locations on the side of my frame & forks, white in the front, red at the rear, to augment the wheel lights.

The wheel lights contain a single bright LED and operate on one CR2032 battery. I use two per wheel. The pack I bought contained one red, one green, one blue, and two multicolor LED's. I put the green and a multicolor on the front wheel, and the red and a multicolor on the rear wheel. I have the blue in reserve in case I lose one of the others.