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.