Nope, not on armor, but on weapons like heavier bombs, most guns, and I think a few swords. Specifically, any weapon that can slow you down while charging it or firing it.

I suggest Movement Speed Reduction Resistance, a UV that lessens the amount the thing it's attached to slows you down by.

"But the slower movement on those things is there for a reason!"
Well, we could make it so each level of the UV only resists a tiny bit, like 5-7% so that you'd still have 58-70% of the movement penalty there. (Not randomly selected, based on what each one would look like in the game. I don't have a way to test these, I'm just estimating.)

"What about weapons that don't slow you down? What will this do for them?"
Nothing at all.

"So I'd just have a useless UV looking ugly on my weapon?"
No; I figure any weapon that won't benefit from this UV just won't be capable of getting it. It seems like there's a way to do that, since bombs can't get ASI and nothing can get sleep-related UVs. (I'd think the old ones would disappear if the UV itself was taken out of the system.)

"Can I get a bunch of weapons with this at once to stack them and become immune?"
Nope, this UV will only resist movement speed reduction caused by the item with the UV.

"Hey, what about Plate armor?"
We could either have this be a UV for equipment in general that slow you down, or a UV for weapons that slow you down. Either way seems fine to me.

"Blitz? Magnus?"
While they do let you move a tiny bit while reloading, which this UV would cover, I don't see why/how it would affect the rooting to the ground. Besides, ASI already helps in that department.

"Does this protect against stun at all?"
Nope, we already have stun UVs for that. Go figure.

"Movement Speed Reduction Resistance is too long of a name, though!"
I don't think it'll really pop up in conversations enough for this to matter too much, but feel free to suggest a different name if you have one.

"Do you really want to just have the ability to buy your way out of any situation?"
See 'But the slower movement on those things is there for a reason!', near the top. It's not like this is giving total immunity or anything.

"Well, I guess it won't break anything, but it doesn't seem like it's really accomplishing much of a purpose."
I still think it would be cool to have, even if it's just nerfed down to essentially a costume UV. It could just be a nice little bonus you happen to get while crafting, not something worth hunting down and buying.

"TL;DR."
I suggest Movement Speed Reduction Resistance, a UV that lessens the amount the thing it's attached to slows you down by.