When roasting veggies together, choose a medley with similar densities which will have similar cooking times as a result. Harder vegetables that roast well together include winter squash, potatoes, sweet potatoes, beets, carrots, Brussels sprouts, cauliflower, and broccoli. Similarly, you can roast softer vegetables together such as summer squash, green beans, red bell peppers, eggplant, and tomatoes.