Here are some filling suggestions for sandwiches to take along when going for an outing or on a picnic.

slices or soft but firm bread

butter
mayonnaise
salad dressing
sour cream
cream cheese
etc

lettuce (eg butterhead)
tomato
bell pepper
radish
cucumber or gherkin
bean sprouts
fresh fruit (apple, pear, peach, strawberry, banana...)
etc

roast beef
cooked tongue
ham
pastrami
sausage
liver pâté
crisp bacon
cooked chicken
cheese (Emmental, Cheddar, Brie, goat cheese, blue cheese, cottage cheese...)
etc

pepper
mustard
horseradish paste
fresh herbs (arugula, basil, dill...)
etc

Butter two slices of bread with the spread of your choice. Top with desired fillings and seasonings. Press slices together and wrap firmly in wax paper.

When eating, peel off wrapping little by little, gradually exposing the sandwich as you eat, preventing the filling from dripping or squeezing out.