Sometimes, I make "ketchup fried rice" which of courses uses ketchup. Same with "ketchup chow mein"
I will also add a bit of ketchup to MaPo Tofu for the Capsaicin-challenged.
Then there are the obvious and common things like ketchup cake, meatloaf, shephard's pie, sloppy joes, baked beans, etc.
Of course there's BBQ sauce, as well as sauces in general, dressings, and chili.