I add lots of veggies to pasta, and rarely miss the meat. My favorite these days is chopped kale and red peppers sauteed with some garlic in olive oil. When the veggies are almost done add a can (drained) of white beans or garbanzos, heat through, and stir in cooked rotini pasta. Season with salt and pepper and top with crumbled feta or parmesan cheese. I usually use a one bunch of kale, two red peppers, and about two cups uncooked pasta and it makes about four servings. This is also good with halved cherry tomatoes instead of red peppers.
Spinach, onion and mushrooms are also good sauteed and mixed with pasta. Sautee the onion and mushrooms with a little garlic, and when most of the liquid is cooked off stir in the spinach until it is wilted. Add a little water to deglaze the pan, stir in a little cream or half and half, and serve over pasta.
For a Thai-inspired flavor, sautee a little garlic in oil. Stir in equal parts peanut butter, soy sauce, honey, and rice vinegar. I usually use about 1 Tbsp of each of these to make a single serving, so 1/4 cup each would be good for 4 people. You could probably cut down on the honey if you wanted and it would still be good. Mix with steamed veggies (broccoli, carrots, snow peas, red peppers) and serve over rice or noodles.
Sorry I don't have specific recipes, I tend to just throw stuff together and it seems to turn out okay.