L.D.
Anything that they can pick up with their fingers and dip always is a big hit. When I cook dinner, I'll usally prepare extra pork, chicken, fish or whatever to dice up into little cubes and serve for the kids' lunch the next day. I also make my own healthier baked chicken nuggests and fish sticks but crushing up cornflakes, baked tortilla chips or potato chips, or crackers and rolling the chicken and fish nuggets in that after tossing the meat pieces in a egg/water bath.
Fruit slices are always good and, if your child can do dairy, you can give them some yogurt to dunk their fruit in. Bowtie pasta is a big hit with my daughter and, since she's a big vegetable rejector, I tend to hide pureed brocoli and cauliflower into the tomato sauce when I make it for her.
When I make pancakes, I'll put some of the batter aside and thin it out with extra milk to make my own version of flat bread, which I use to wrap up peanut butter & jelly, lunchmeat and cheese or whatever, before slicing the wrap into discs and serving.
Hope this give you and your little guy a bit more variety at lunchtime.