Basically there are no specific smoothies that are good for fat loss, but there are some that nutritiously healthy probably better to have rather than others as part of a balanced diet.
First off, you should probably avoid the off the shelf smoothies as quite a few have a high sugar content. When trying to shift fat sugar is probably your biggest enemy. So if you do buy one, check the sugar content first. If you’re going to make one think about what ingredients you choose, and remember that fruit has a lot of fructose! This is also a sugar and too much is just as bad as having syrup everyday. I’m not big on smoothies so I’m going refrain on giving a recipe but I would say for a protein rich smoothie look at milk, peanut butter, with a little fruit. For a bit and minerals one you should probably go half and half green vegetables and fruit. There’s plenty online that’s probably better than what I’d recommend recipe wise. But remember if it’s high in sugar it’s going to not help fat loss and probably do the opposite.