Oven roasted vegetables are a phenomenal way to add variety to your plate, and are very filling. They can all be roasted at 400⁰ F, so you can prep them simultaneously. Cauliflower, broccoli, beets, carrots and squash are all great options. If you select thin-skinned squash you don't even have to peel it.
Even easier, you can just take a bag of frozen mixed veg and roast it. I open the bag, toss in some olive oil and an herb of choice then spread on a baking sheet and roast at 450 until done. Crazy fast and easy.