Google plus addressing format and the unanswerable question

Google supports something called plus addressing, which is just username+alias@gmail.com or username+alias@example.com if you are signed up for their domains product.

The alias/plus addressing is not exclusive to google. I have searched, posted on forums, asked around, and no one can seem to find a way to search gmail, or to create a filter that can locate all plus addressed emails.

As an example address: user+amazon.com@gmail.com

If I forget to add a filter for user+amazon.com, and really who has time to set that up right on the spot. Further, gmail doesn't exactly show you must of the recipient address other than "me" unless you dig deeper into each email.

I want to be able create a filter that says if any To: address has a plus in it, mark it with a label.

I have tried regex, which I don't, believe is supported. I have tried what I thought should work, as just to: user+ for which it finds all my email. And finally I have tried to just search To:+ and To:"+" as well as other variations.

Any suggestions, a plug in, anything?

Thank you.