UV Squares is a simple add-on that helps you to align your UV Map into a grid. It has a few tools but the primary tool is accessed with Alt+E.

• Select your UV map partially or in full
• Press Alt+E
• UV squares will try to make all individual faces square, aligned in a grid.

We can also rip and join faces with this tool. Invaluable UV Mapping tool when you just can't get that straight UV Map any other way.

UV Squares is available on Github for free but you can also support the creator by buying it on Blendermarket.