UniV

Blender Addon for UV Editor which aims to cover all sorts of operators for working with UV

Quick Snap - allows you to transform an island or geometry elements by Vertex, Edge Center and Face Center. There are two methods of calling the operator via the keys:

Weld - [W] connects selected vertices by common vertexes, if there is nothing to connect, it works as Stitch

Alt+Weld Button - connect by distance

Stitch - [Shift+W] connects islands to each other, preserving the islands' proportions. When called via keymap with sync enabled, the target island becomes the closest:

Stitch with padding

Unwrap - differs from the built-in operator in that it unwrap inplace.

Relax - combination of minimize stretch and unwrap borders.

Cut - [C] - sets mark seams by border selection and at the same time expands the island

Quadrify - [E] align selected UV to rectangular distribution

Straight - [Shift+E] straighten selected edge-chain and relax the rest of the UV Island

Copy to Layer - copy coordinates between uv-channels

Adjust & Normalize - sets a uniform texel

Flatten - convert 3d coords to 2D from uv map

Focus - [F] improved focusing, which frames the focussed elements.

Crop - proportional tile filling

Fill - it is similar in everything with Crop, but without preserving the proportions

Orient - orients islands along the axes, maximally filling the area according to the boundbox. In a 3D viewport, it .

Orient3D - orients islands according to world coordinates.

Align - straightens, moves islands or vertices, places a 2D cursor on bound boxes, etc.

Sort - sorts islands, also aligns for more compactness.

Distribute - similar to Sort, but the goal is to arrange the islands evenly according to the original position

Random - randomly transforms islands to break down repetitive patterns.

Linked - [Ctrl+Shift+Mouse Scroll] - Select Linked

Cursor - Select by Cursor

Border - Select border edges

Border by Angle - Select border edges by angle from 2D

Inner - Select inner edges by mark sharps, angle

Square - Select square, horizontal or vertical island

SyncUVToggle - [~] toggle sync mode with element selection preserve

SplitUVToggle - [Shift+T] open, close, toggle UV or 3D View area

There is much more to UniV operators than you might think at first glance. Many operators are context-dependent, for example, on Sync state, selection mode (Verts, Edge, Face and Islands), as well as on pressed Ctrl, Shift, Alt (CSA) keys and combinations thereof.

That is, before pressing the LMB button press CSA, then other modes of the operator are called. And these modifications are subject to a certain logic, which in most cases works:

But you don't have to use the CSA keys, because a panel appears in the lower left corner where you can change the properties

Also, the addon doesn't impose its hotkeys on you, but you can easily enable them in Settings->Extensions->UniV->Keymaps. But some operators due to their specificity can be called only through keymaps (QuickSnap, SplitUVToggle, SyncUVToggle).

The addon is free, but you can support the author and purchase this addon from Blender Marketplace