Vegetables that do not fall apart easily and retain their texture after roasting are ideal for the grill. Here are some suggestions:
Peppers - great for grilling because they have a stiff skin that helps them hold their shape when turning.
Eggplant - grilled eggplant is very flavorful and soft inside. It can be sliced or halved and baked without the skin.
Onions - onions are easy to grill because they are firm and have a stiff texture. It can be sliced or halved and put on the grill.
Zucchini - it has a delicate skin, but retains its texture when grilled. It can be sliced or halved and baked with olive oil.
Mushrooms - mushrooms are great on the grill because they have a strong flavor that is enhanced by grilling. They can be roasted without fluttering and cut into smaller pieces.
Corn - corn is ideal for grilling because it has a stiff skin and sweet flavor. It can be roasted whole ear or cut into smaller pieces.
Keep in mind that any vegetable can be grilled, but some will require more attention when turning so they don't fall apart. You can also try grilling other vegetables such as zucchini, pumpkin, asparagus, broccoli, or cauliflower to create your own original flavors.