I believe that a sandwich (and yes, a burger is a type of sandwich) ain’t a sandwich if it don’t have tomatoes, cheese, or condiments (I love mayo, or mustard, or ketchup, or guacamole).
On my hamburger (if it’s a beef one), I like a cheddar cheese single, some relish, a juicy tomato, ketchup, and mustard.
If it’s a chicken burger, I like mayo (garlic mayo is YUM or even tartar sauce)…cheese…finely chopped lettuce…and a tomato.