Open faced sandwiches. Cereal isn't super common but kids like it because it (usually) has lots of sugar. Warm meals aren't common for breakfast/lunch but people will sometimes have fried eggs and bacon.
But mostly just open faced sandwiches with ham, cheese, cured dried sausages (like salami, or our own types), various salads (prawn, crabstick, chicken....), the usual stuff.
Some, like me, enjoy pickled herring. There's also canned mackerel in tomato sauce, usually topped with mayo.