I wouldn't want to only cook like this: every restriction you put on your cooking makes it harder. (Not specific to cooking!) Still, there are a few meals that do work well this way. For example, this is the main situation where I'll cook baked potatoes with stuff to put on them:

• Baked potatoes
• Black beans
• Cheese sauce
• Ground beef or bacon
• Caramelized onions
• Roasted cherry tomatoes
• Chopped scallions
• Olives
• Sour cream
• Baby spinach

This is mainstream American food, but because each person chooses what goes on their plate it works for nearly everyone: vegetarians leave out the meat, vegans leave out the cheese and cream, low-carb people leave out the potato, potato-only people just eat the potato, there's no gluten, etc. Which exact sides you choose don't matter too much as long as you think a bit about dietary categories. I'm probably listing a few more than I would normally make.

If I didn't want to make potatoes I'd do tacos/burritos, without trying for something authentic. This could be:

• Corn tortillas, briefly heated
• Flour tortillas, same
• Black beans
• Grated cheese
• Ground beef, chicken, or carnitas
• Pico de gallo
• Salsa
• Roasted bell pepper slivers
• Guacamole [1]
• Sour cream
• Baby spinach

And yes, this has a lot in common with the previous meal, but the spices are pretty different and I wouldn't mind serving them on consecutive days.

Other meals where there are a lot of options on the table and each person chooses their own combination also work. The main things I keep in mind are trying to keep each component relative simple, having at least two protein options, at least one vegan protein option, and at least one non-glutenous starch option.

[1] I usually don't make guacamole, because I don't really like it and I prefer not to prepare food I don't enjoy. It's not that I object to other people enjoying things when I don't, it's that my cooking involves a lot of tasting things and that strategy falls apart if you can't tell which direction is better. But it definitely belongs on this list if I'm not cooking, and even when I am a housemate will often make some.