Vegetable Smoothies (not fruit smoothies)

I'm on a low-carb diet and I'm trying to increase my vegetable intake. I typically have about 2-4 cups of leafy greens and one serving of a different vegetable every day. But I often skip that second vegetable for various reasons.
I've started adding spinach to my protein shakes and I'm wondering about other vegetable smoothie ideas.

The problem is that my searches have yielded - not what I would call vegetable smoothies - but fruit smoothies with vegetables added. Being on a low-carb diet, I can't eat a lot of fruit in one day. And the fruit that I do eat, I prefer to eat whole and by itself because that's how I enjoy it most. That said, I do add a 1/4 cup of berries to my protein shakes to sweeten it some. But that's about as much fruit as I'm willing to add to a shake or smoothie.

Do you have any recipes for good vegetable smoothies that aren't so heavily reliant on fruit or other carb-heavy ingredients? Like I said, some fruit is ok. But I'm looking for primarily vegetables.

Please only respond if your response is relevant to the question. I've already done the research; I've already decided it's what I'm doing; and I'm finding it works for me. So if you disagree with that decision for whatever reason, please keep it to yourself. Sharing it here is counter productive.