I mean for a case like this: I have multiple uv shells selected and stacked, and I have uv editor grid setup to match my tileable textures. But now I want to
snap and scale uv shells so that it matches the texture.
I feel there should be a tool in UV Editor or UV Toolkit that can do that, but I couldn't find one. Any suggestions?

Replies
With that I can select UV vertices and use the usual x key to snap to grid while moving uv vertices.
Haven't found an automated way yet, but this is at least do-able now.