Blender - Download Easeam - An Easy And Quick Way To Marking Seam (Uv Unwrap Tools) v1.2

Blender - Easeam: This extension will speed up unwrapping, particularly when marking seams.

Tips:

Every part of the add-on's interface has an explanation tooltip. If you're unsure what it does, move your mouse over it.
If you intend to utilize these tools frequently, I suggest assigning a "Shortcut" to another operator that you wish to assign
It would be best if you right-clicked the button you wish to assign to accomplish this.
If you're comfortable enough about this add-on, you can hide the N panel from the add-on's preferences and then access the add-on via shortcuts you've assigned or the pie menu

New Changes:

Some great features of Blender - Easeam:

Mark Around Flat

Edge seam markings around connected flat surfaces can be set with an angle and can be used to increase the range of options.
You may also mark on the selection faces setting both values to 0
Also, it is possible to automate unwrapped without "Live Unwarp" (Enable "U" icon)
It wouldn't be a problem crossing over UV island.

Seam Edge Loop

Choose Edge Loop and mark the seam
capable of auto-unwrapping ("U" symbol) and between seams marked with Live unwrap disabled
Don't you think that crossing the edges has already marked the seam?

Tube seam