Since RTO I've doubled down on bento/snacking style lunches. Think "Starbucks protein box" type things. Cheese cubes, boiled egg, crackers, peanut butter, apples, grapes, olives, hummus, cut veggies, edamame etc. It's endlessly changeable.
I also bring breakfast which is either homemade bran muffins or a big pot of apple/nut oatmeal that I make at the beginning of the week and heat up at work.