I have just encountered an issue where Google is constantly blocking certain extension from being active in Chrome that is supposedly violating its terms. The thing is - this is an extension that hides an advertising sidebar on any Facebook sub-websites.
This is quite annoying and that was a quick fix by copying the existing plugin, changing the metadata and side loading it.
If you experience an extension that is blocked and you still want to use it - this is the way to go. Please note that most blocked extensions are blocked for a reason and you are doing this at your own risk. Some malicious extension can steal sensitive data, so be very careful.