Hi there,
Here are a few scripts I use in production:

File TextureManager by Feng (Mark) YE

Tip: The Browse feature is broken. Maybe I’ll fix it later.

Multiple Connection Editor (MEL) by Jim Collins

Interactive Boolean Tool (MEL) by Sean Puller

Random Object Selection (MEL) by Jordi Fernandez Mora

Select Similar (MEL) by Hesham Eissa

Multi-Transfer Attribute (python) by Nestor Prado

Tips:
The indentation is important!
Not just for UVs.
You can customize what and how to transfer by changing the flags and the numbers in last line. More info.

Hard Edge Selection Scripts by me 🙂

Super simple, but it’s so much faster than the Use Constraints… panel.
Update! Sorry I missed a flag 🙂 Now it works every time.

//Convert the Current Selection
ConvertSelectionToEdges;
polySelectConstraint -m 2 -t 0x8000 -sm 1;
polySelectConstraint -sm 0;

//Constant Hard Edge Selection
polySelectConstraint -m 1 -t 0x8000;
polySelectConstraint -sm 1;

//Clear Selection Constraints
polySelectConstraint -t 0x8000 -sm 0;

Cheers, D