Select UV Seam

The Select UV Seam command (Selection > Maps > Select UV Seam) automatically selects polygons where the UV values span more than half the image - thus assuming that they are seam polygons. If you activate Patch with Poly Map, it will automatically turn these into per-polygon UVs.

Select UV Seam is limited, because it will not set UV values past 1.0 or less than 0. Thus, it is possible that some important portion of your image will get missed (e.g., you really needed a 1.2 U or V value).

The Select by Map command (Selection > Maps > Select by Map) selects or deselects points that have entries in the chosen Vertex Map.