I grew up on frozen sandwiches. My mother made lunches for four every sunday afternoon with fresh bread from the markets. The sandwiches did tend to get a bit boring as they were devoid of salad.

Our stock standards were:
roast pork with apple chutney
ham with mustard
chicken/turkey with cranberry sauce (better still, left over roast chook).
lamb and fruit chutney
salami with tomato chutney
cheese (brother always had cheese and chutney)
devon & tomato sauce (other brother had this for a year!)
vegemite
vegemite & cheese

and that was about it.

Basically any deli meat and chutney/sauce combination doesn't defrost into a mushy mess. Be scant with the sauce though.

We never ever had any success with any fresh salad or vegetable ingredients.

Oh and her other secret was two layers of gladwrap on everything!