Most days DS has his cold meal in the evenings as well -- except on days when he didn't like the lunch at kindergarten and didn't eat, then I make him a warm meal. I do rolled up slices of deli meats or cold turkey sausages, cold frikadella, chopped up fruits, vegetables (either raw, cold or from a tin - he loves tinned carrots just cold on his plate, as well as tinned corn). I buy frozen peas and just put a handful in a coffee mug and pour boiling water over them until they are not frozen but they are still rather cold and he loves them. He also likes baked beans right out of the fridge. Sometimes I make up a huge batch in my slow cooker, other times I buy them tinned.
Cheese on toast, I realise it is cooking and 'warm' but it still falls into what we call our "picnic" meal -- I use rye bread and put a slice of cheese on it (edam, gouda, butter cheese, or sliced hard cheddar) and pop under the grill in the oven until is starts to melt. Cut it into strips and DS will eat it once it has cooled.
Crisp breads with fresh cheese, quark, jam or peanut butter - DS prefers the puffy crisp breads rather than the Wasa bread style. I can't think of the name of them right now but they are in a red box and come in wheat, rye or wholegrain. He likes raisin breads from the bakery, sometimes I slice one of them up and use them to make his french toast.
He has a yogurt most every day with his evening meal.
Peanut butter and banana sandwiches on soft whole grain bread (the kind they use here for toast rather than for sandwiches).
Does your DS eat fish? DS won't eat smoked salmon now but he did when he was little.
I'll see if I can think of anything else!