If you're traumatized by oatmeal, you could try some alternative grains: farina/cream of wheat cooks up fast (make it with milk and a little sugar, all the kids I've ever known loved it! You can also add fruit, jam, honey...); millet or buckwheat you can make the night before and they'll reheat well. Or, cooked buckwheat groats (cook them just like rice), can straight up replace cereal...just add milk.
My parents were night owls and I have fed myself in the morning since I was in elementary school (oh, and I'm not much of a morning person either). Favorites have included frozen waffles (sometimes topped with yogurt), pancakes, and french toast. Once I started being more mindful of the sugar, I also liked sandwiches (cheese, deli meat, or PB on bread or toast) with a cup of hot tea.
In grad school I got addicted to DD breakfast sandwiches, then bought a box of frozen, then realized I could make my own. You can bake eggs in a muffin tin with or without ham, veggies, etc. mixed in, then put them on toasted english muffins, wrap, and freeze. Remove and microwave in the AM. Or skip the bread and just do little egg muffins. Maybe with a bit of pie crust. I also went through a breakfast cookie phase; I second those. Homemade muffins can also be full of good grains, fruit, nuts, and fiber (and you can limit the sugar).