I would contend that there are no foods that taste better as leftovers. Food made hot is meant to be eaten hot. Food made cold is meant to be eaten cold. The only time that I can imagine food being better is if it's meant to sit and marinate for a while, and in that case that's just the way it was intended to be eaten. So it's not really leftover then, is it?
I personally feel like most pasta meals taste a little bit better a day or two later. I think it's maybe because the noodles start to dry out or like the sauce starts to dry and become thicker. But like, for example, lasagna, like I love how that tastes, you know, a couple, a day after or two or spaghetti. Those are really, really good. By the way, spaghetti and mac and cheese taste really good with scrambled eggs as leftovers.
I reject, I reject the idea that this is possible, that tastes better as leftovers. I guess maybe like the one thing that I think of is like Thanksgiving pie, but I don't know if it tastes better, but like it's just so good the next day too. But even like pizza and stuff like that, some people are like, oh cold pizza is like better than like when it's right out of the oven. That is false information, and anybody who says that, you should probably stop being friends with them.
Most Italian foods I'd say taste better as leftovers. I think lasagna, spaghetti definitely tastes better as leftovers. I might even say I think pizza tastes better as a leftover. I'm not quite sure on that one.
My family's go-to favorite leftover is chicken enchiladas. They like it when I make them but they like them even more the second day when they heat them up.
I do think spaghetti and meatballs is pretty good most of the time if you know how to cook it right or reheat it right without it like exploding and making a huge mess all over the microwave, but I think that one's a pretty good one.
I think pizza is very good when it's in the fridge and you can dip it in ranch dressing.