Help! I only know how to make egg sanwhich

How about ham and cheese or turkey and cheese? I just add a little tomato, maybe some lettuce or spinach leaves and some mustard. If you like mayonnaise, then add it too. Or there's always peanut butter/ peanut butter and jelly/ peanut butter and honey.

There are a variety of veggies that you can use of course, a great way to get your greens with your grains (if you use whole grain bread). I love tomato and cheese either fresh or turned into a fried sandwich. Some cream cheese adds a creamy touch to lettuce, olives, tomatoes and cucumber. Nut butters are fun to explore with, I prefer almond butter although in the US it's peanut butter that reigns as king. Plain nut butters are good, or serve with jam/jelly as someone mentioned. They can also be combined with fresh fruits, banana being a common favorite - also try apples for a fresh crunch. Tahinican also be used, although your kids might be too young to like it since it has a bit of a bitter taste. Hummus is a great addition to sandwiches, especially if you fry up some falafel balls (ready made mix is available) to go with it. Or serve hummus with red bell pepper, very good. For a twist on the regular egg-salad sandwiches, try mixing hardboiled egg with fresh margarine or butter (instead of mayo) and serve in a smaller quantity to make up for the additional flavor and fat. My favorite sandwich is anything with cheese, and there are hundreds of different cheeses in the world. Good with cheese include tomato, grapes, apples, roasted red bell pepper, sundried tomato, and lots of other veggies. Don't be afraid to experiment, and add variety by using different types of bread! I recommend searching for panini recipes, because even without a panini grill you can easily fry them in regular pans.

I love tuna sandwiches (or use tinned salmon for a change), roast chicken salad sandwich, BLT, grilled cheese (with some onions if you like that), ham (with cream cheese and salad)... lots of stuff!

tuna or flaked chicken is good

Grilled cheese is always a good one. But you can put anything between two pieces of bread, I think maybe you're thinking it's harder than it is or something.