We used Mini Triscuits which I learned a while ago have two ingredients: wheat and salt. (Ditto for regular Triscuits, of course.) Plus extra sharp cheddar cheese. Our kids have Euro-tastebuds when it comes to cheese, the stronger the flavor the better. Use whatever kind of cheese yours enjoy.
And berries. Don’t forget the berries.
Tip: If you make this ahead of time, put a damp paper towel (or several) over the top of the berries and cheese. That’ll keep them from drying out in the fridge–but don’t put towels on the crackers. Or just use a tray (or baking sheet with a lid). I used a cutting board, and the whole thing sat for an hour or so at room temperature without any trouble at all.