Scrambled eggs with blueberries on a sandwich are also very unusual for me!Unusual depends on where you live and how you were brought up...
I hear people talk about peanut butter jelly sandwiches or blueberry scrambled eggs and to me they are highly unusual !
(Chips on a roll (chip boetie), spaghetti bolognese on bread etc)
Now to think of something I eat on sandwiches that are unusual...
Chili paste, mustard, deep fried onions and boerewors maybe?
But that idea was stolen from Denmark