When it comes to Devil Fruits, I have a habit of thinking about how much potential each one has. I believe that there are no bad Devil Fruits, only bad users. (Unless it's one of those crappy non-canon ones.)
So let's begin with my favorite Logia fruit: The Yuki Yuki no Mi.
Please Note:
These are strictly my headcanons as to what a Devil Fruit is capable of doing. Nothing is official unless Oda says so.
Many people don't give this fruit enough credit because it's considered inferior to the Hie Hie no Mi, because it's not as strong of a freezing agent as it.
But freezing things solid is not where this fruit's potential lies. After digging up some research, I learned that the Snow Fruit is like the distant cousin to the Suna Suna no Mi, and is capable of doing a lot of things similar to it, perhaps even more.
Here's a few similarities in question:
The Sand Fruit can drain the moisture out of people, animals, etc. In the same way, the Snow Fruit can be used to drain the heat out of people.
The Sand Fruit can reduce things like stone, plants, and people, into sand. In a similar sense, the Snow Fruit could be used to powderize ice, transforming it into more snow.
Both are capable of creating whirling storms, which can be used to fling people into the air or obscure one's vision.
If eaten by someone with an active imagination, the Snow Snow Fruit can be used to create weapons and constructs out of hardened snow (which has been shown to be strong enough to pierce through flesh and bone). Combine it Busoshoku Haki, and they become even deadlier and immune to melting.
Imagine transforming into a giant snowball and flattening anything in your way, or using snow to change your body into the forms of mythical creatures like centaurs, lamias, or even krakens.
Not to mention, you could transform into a giant made of snow and CRUSH THOSE WHO DISOBEY YOU!
If you have any more ideas for this fruit, or any other fruit, let me know in the comments before.