In no particular order:

Reuben

Peanut butter and banana on wheat bread

Peanut butter and pineapple (canned slices are okay to use, but you have to blot them on a paper towel or the bread will get mushy) on wheat bread

Fried bologna (it's gotta be the extra-thick kind), a fried egg, cheddar cheese, and mayonnaise on toasted white or sourdough bread

Roast beef and Swiss cheese with spicy mustard (Zatarain's Creole Mustard is best, but use it sparingly if you're not used to it... think of it as Southern wasabi) on pumpernickel.