Bear in mind: washing out the little boxes can be a pain... I tend to have one go AWOL every couple of weeks, to be rediscovered with a rainforest of mould in it. You also need to stock up at the pound shop for disposable forks.
I'm not sure if you're on the right track with mn - pasta/tue- rice /wed - pasta etc. I think the way to do it is to make up a big bowl of something and then eat it until it runs out (i.e. 2-3 days with the same lunch box). Then make something else, and eat that for a few days. That way the food is fresh - not nice when things start going off. You still get variety, but over a longer timescale.
Pasta:
JO has a good recipe - something like pasta + a couple of toms chopped + cucmber + olives + onions with a bit of olive oil and lemon juice as dressing. Some sweetcorn doesn't go amis either - mozzarella if you have it - basil if your family eat it. Doesn't freeze though.
I also make pasta + tin toms + squeeze ketchup + assorted veggies/chicken. It's good hot for dinner and cold for lunch.
I sometimes copy the M&S mustard chicken pasta (half half mayo and yogurt plus a tiny bit of coarse mustard mix inb with cold pasta chopped chicken and sweetcorn.
Potato:
I like 'salad nicoise' kind of things. Basic mix: boil spuds, while still hot roughly chop and chuck in extra virgin olive oil and lemon (absorbs loads better if you do it while hot). Then chopped onion, chopped tomato, lightly dooked green beans, olives, tuna, boiled egg. (leave out and add things as you wish).
Btw - my Dh accuses me that my cooking always has lemon in it - which is pretty fair!
Have you thought of cous cous? Similar idea: cook it, chuck some dressing in while warm, then brighten up with chopped salad veggies.
Bean salads:
Tin of white beans (e.g. butter beans) plus - you guessed it - lemon, oil, toms and onions.
I also sometimes pack a pitta bread or a bread roll separately, and then provide a tupperware with something like houmous, chicken+mayo+curry, grilled chopped sausages+relish etc. Then they can assemble sandwich on site.
Another option: make a sandwich mix. i blend a tub of cream cheese+kidney beans+a bit of curry powder (can use oregano instead if you want it to taste 'italian'). Then I just spread it on sliced bread - much quicker than making propoer sarnies.
Now (best til last) my patented discovery - I think this is the bees knees! Last week I bought a big bad of baking potatoes on offer, and disciovered at home they were quite short dated. I made 'jacket halves' - just as easy to grab and go in the morning, and no tupperware to retrieve and wash at night. Not sure about freezing - but can be warmed up in evenings.
Kifs cheesy jacket halves:
Buy 5kg bag of baking potatoes and cook them in the oven until soft inside (poke with a skewer to check). Leave them to cool for a few mins (leave the oven on). When they are cool enough to handle with a teatowel, cut each one in half and scoop out the flesh. Don't be too precise - leave plenty of flesh on the skin and be sure not to burst. Put the dug out shells back in the oven for about ten mins or so. This should be enough time for you to mix the potato flesh with:
Chopped spring onion
Creme fraiche or greek yog
salt and pepper
plus your choice out of:
cooked peas
chopped ham/bacon
tuna
cheddar cheese
Mix all that up, take the shells out the oven, fill then up with mix. Sprinkle grated cheddar on top - back to the oven until golden and bubbly.
Take out - cool down - easy lunches!