You could substitute other vegetables for the ones listed - broccoli, carrots, parsnips or squash would all work great. Use any flavoured sausages you have on hand.
Preheat oven to 400 degrees and line a baking sheet with parchment paper.
Combine all the vegetables in a large bowl. In a small bowl, mix together the olive oil, mustard, salt, pepper, and oregano. Pour over the vegetables and toss until coated.
Spread out vegetables evenly on a baking sheet and place the sausages on top. Bake for about 30 minutes. Flip the vegetables and sausages and bake for an additional 30 minutes until vegetables and sausages are browned and tender.