My first aid kit started as one given to me when I did a first aid course for work. It's a belt pouch version, 2x3x4" in size. It's now packed full, and from what I can remember that's in there (don't want to unpack it unless I need to):

small, regular & patch band-aids
knuckle band-aids
butterfly band-aids
3x3 & 3x4 gauze pads
2" and 3" gauze roll
2" elastic wrap
2 small rolls tape
abdominal pad
scissors, tweezers & safety pins
triangle bandage
alcohol swab, iodine & burn packets
benadryl (I have a bee sting allergy, don't need epi though)
pair of gloves

There could be some other stuff in there, the kit itself is packed full. I also carry a survival kit, about the same size container, which also has some first aid things in it.