I really like grilled cheddar cheese sandwiches with a slice of tomato in the middle. Ham or bacon and tomato grilled cheese is good, too.
Now I might have to try a tomato grilled cheese this weekend. :)
Another great way to make grilled cheese is to add thinly sliced apples or even pears in the sandwich too.
My ex MIL used to make something like that, open face. Bread then Cheddar, then tomato slice, then bacon. Broil. Delicious. (I’d forgotten all about that until I saw your post.)