Many veggies taste better roasted. I do them without oil but using a little bit is quite healthy. Halved or quartered bell peppers, Brussel's sprouts, large chunks of onion, or thin or quartered carrots... Just toss with a little sprinkle of oil, some salt and pepper, and maybe a tablespoon of balsamic vinegar and spread out on a baking tray in a not too hot oven (mine's on 160-180°C, no idea what that is in Fahrenheit) and let sit until they go soft and the edges start to char. I'm sure the internet will spit out exact numbers for each veggie if you search for them.