A set of useful tools for working with Unwrap.

- Conversion of selection of vertexes, edzhey, polygons.
- Selecting the open faces of the mapping.
- Transfer the selection from Unwrap to Poly and vice versa.
- Flatten and Box mapping in real size.
- Normalization of the mapping scale.
- Height / width alignment.
- Vertical / horizontal alignment.
- Switching texture material in the viewport. Bitmap, Corona Bitmap, FStormBitmap.
- Quick cull and display material backface switches.
- Non-destructive checker materials. The source material can be returned in any case. You can add / remove textures in a folder.
- Create anti-aliasing groups from the mapping.
- Creation of flat geometry on the basis of mapping in the sizes of the initial object.
- Interactive change of mapping without opening the UV editor.
- Randomization of mapping on shells or elements of geometry.

And also other additional functions with Shift / Ctrl combinations. Each is described in the tooltips on the buttons.

Link to Blog with version 2.0
https://3dsky.org/blog/post/uv_tools_2 

Differences from version 2.1 in the comments.