I love mushrooms as an alternative to eating tons of meat or dairy products. I buy the big portabella mushroom caps, flip them upside down, and use it as a 'pizza' base. I top with some veggies, maybe even a little chicken or lean meat, and a little cheese. Bake until the mushrooms wilt and cheese melts. It's absolutely delicious and mushrooms pack a ton of protein considering they're just a veggie and most veggies are high in carbs.
I also love to toss the mushroom caps in some olive oil and basalmic vinegar, bake until they wilt, and then slice. Put those with some extra veggies, maybe a little hummus, in a low-carb wrap and have as an alternative to sandwiches.
Speaking of which, I love hummus or salsa with veggies on the side for dipping, as opposed to chips or breads, as a quick snack.