In a small bowl, combine the garlic, rosemary, oregano, basil, olive oil, lemon juice, and a pinch each of salt and pepper. Whisk well.
Lay salmon fillets, skin-side up, on one side of the prepared baking sheet and brush with one-third of the herb mixture. Flip the fillets over and brush with the remaining two-thirds of the herb mixture.
Spread the zucchini, mushrooms, bell pepper, and tomatoes on the other side of the pan, then drizzle with olive oil and season with salt and pepper to taste. Toss well to coat.
Bake for 30 minutes, or until the tomatoes are bursting and salmon flakes easily.