Well, anything that she is happy to eat!
DS2 has always had a lunchbox (DS1 prefers school lunches) and usually has:
A sandwich (I vary between white, wholemeal and added fibre white bread - he prefers white but knows that he can't always have that)
Fillings vary little, and are usually ham, cheese or sliced turkey.
I also bought a flask so sometimes instead of a sandwich he takes in something leftover from the previous night's dinner - pasta and sauce or risotto, for example.
A carton of fruit juice - organic usually
A piece of fruit
A packet of crisps (Potato Heads or Walkers Lower Fat)
A sweet treat of some sort - usually a chocolate biscuit, sometimes a cookie or two. If I'm being a really good mummy I might bake something, but this is rare . I know that some schools ban this, but I've always ignored this as DS2 is stick thin and therefore in the overall scheme of things I don't have a problem with him having this.
Sometimes a yoghurt-type pudding, but these days often not.
The thing that you have to accept with packed lunches is that no matter how healthy they are, what they eat is actually out of your control. Swapping food is a regular occurrence! And it's amazing how often the sandwich or apple come back uneaten.
Oh, and once he got to senior school, Yr 7, he started making it himself.