We also just rotate through protein themed nights, without necessarily planning specifics until the start of the week. I still find it infinitely easier to know that it is egg night, so I am picking a dinner with egg as the central protein (and if I didn't mess around with the schedule, we will have had other non-egg proteins the days before and after so lunch leftovers will be varied.)
We rotate through:
- Non-bean legumes/Soy (falafel, stir-fry, soup, etc.)
- Eggs (omelets, quiche, shakshouka, breakfast-for-dinner, etc.)
- Pizza/Pasta
- Meat (sausages, roast chicken, etc.)
- Beans (burritos, tamales, chili, etc.)
- Fish
...with one floating night (usually Saturday) that is usually takeout and occasionally meals out with friends or other meals not at home.
We obviously don't eat much meat, but you could easily do the same rotation and just add a beef/chicken/pork night, etc. We always have salad and then have whatever grain or other fish goes with the main meal.