How small do you want to go?
Smallest is my key chain (hotspark, micra, whistle, pill case w/ cotton ball, advil, immodium and benydryl), pocket knife, Vic Climber (which has a Fenix EO1 on it).
Next step is my
PSK. That is part of my EDC, which adds cordage, lights, batteries, knives, tools, emergency poncho, contractor bag, nalgene, cup, compass, maps, gloves...
And that is what I carry when I'm in my town. *blush*