My local bagel spot sells a scrambagel, which is toasted bagel sandwich with scrambled eggs, green onion, butter, and cheese. When I buy it there, I typically add sprouts. I've also been making this sandwich at home and I'll add more veggies like kale or onions to make it even more hearty and douse it in hot sauce. Definitely one of my favorite breakfast items ever.
Another go to breakfast combo that I make at home a lot are sunny side up eggs with hash browns and toast with butter and jam. Super quick and easy while being very filling. My partner makes oatmeal a lot and will spruce it up with some mixture of peanut butter, cinnamon, granola, and fruit. We've been using a lot of date syrup lately and it also goes really well in oatmeal.
One of my favorite breakfast combos of all time, and one that I can't get where I live now, is youtiao (
https://en.wikipedia.org/wiki/Youtiao). It's essentially long strips of fried dough that can be sweet or lightly salted. It's a very traditional Chinese breakfast food and you can buy them from food carts all over Beijing. They're typically served with fresh soymilk, and boy is that an amazing combo.