I'd like to clean up my Gmail inbox and want to search for messages from people who are not in my contacts.
Ideally it would be something like:
is:contact isn't an actual advanced search operator/value.
It's not the most efficient way, but you get results.
Export your Gmail contacts into a .csv
Extract the names from the .csv (with Google Docs)
Create a massive filter with all the names
from: -(name1 OR name2 OR name3)
This last step will probably be best done with a string/file manipulation macro/script. If you'd like to try it, I can write one in AutoHotKey.
I've been searching for the same thing recently, and it looks like not much has changed.
The closest thing Google makes available is the
has:circle advanced search operator.
According to Google,
Search for all messages that were sent from someone who you added to your Google+ circles