In the same way that a headlight reflector can be used as a parabolic reflector to start a fire, the reflector from any flashlight that uses a bulb can be used. This doesn’t work so well with the newer LED flashlights, as they have very small parabolic reflectors and the LED is permanently mounted to it. The larger the diameter of the reflector, the better, as it will reflect more light, creating a hotter focal point.
Just like the headlight, you can put the tinder in from the back of the reflector, through the hole where the bulb would normally mount. Point it at the sun and as long as you have a clear sky, you should see smoke within seconds.